BRUSSELS — The Latest on the explosions Tuesday at Brussels airport and a subway station (all times local):
The Islamic State group has issued an updated communique taking credit for the Brussels attacks and threatening other countries taking part in the anti-IS coalition.
The statement promises "dark days" for countries allied against the Islamic State, threatening that "what is coming is worse and more bitter."
The communique was published in Arabic and French, and an English translation was provide by the SITE Intelligence Group, which monitors jihadi websites.
IS also released photos purportedly showing its fighters in Syria giving out candy to children to celebrate the Brussels attacks, according to SITE.
A Belgian security official says the death toll has risen to 34 in attacks on the Brussels airport and a subway station.
The official did not specify how many people were killed and wounded at each site. The official spoke on condition of anonymity because precise numbers were expected to be announced early Wednesday.
Earlier, the government had reported 20 dead at the Maelbeek metro station, in the heart of the European Union's capital, and 11 dead at the airport, and scores of injured.
The Islamic State group claimed responsibility for the attacks.
President Barack Obama has ordered that all American flags in the U.S. be flown at half-staff through Saturday out of respect for victims of the Brussels attack.
Obama said in a proclamation issued hours after Tuesday's attacks that "the American people stand with the people of Brussels. We will do whatever it takes, working with nations and peoples around the world, to bring the perpetrators of these attacks to justice, and to go after terrorists who threaten our people."
German police say three Kosovars who are suspected of possible links to an extremist network have been arrested on a highway in the south of the country.
The state criminal police office in Bavaria confirmed a report by broadcaster Bayerischer Rundfunk that the three were arrested early Tuesday on the Munich-Salzburg highway, news agency dpa reported.
According to the report, they were in a Belgian-registered car. However, the criminal police office said that there are no indications at this point of any link with Tuesday's attacks in Brussels.
Police in the Belgian capital are calling on people who may have filmed images from the attacks on the city airport and subway to help assist with their investigation.
Brussels police called in a statement late Tuesday for help from "anyone who has amateur film where the attackers may be in view and could help move their investigation forward."
The U.N. Security Council has strongly condemned the Brussels attacks and urged intensified regional and international efforts "to overcome terrorism and violent extremism."
A statement approved by the U.N.'s most powerful body expressed solidarity with Belgium and underlined the need to bring those responsible for "these reprehensible acts of terrorism to justice."
The Security Council again urged all countries to combat "terrorist acts" and take measures to prevent and stop the financing "of terrorism, terrorist organizations and individual terrorists."
U.N. Secretary-General Ban Ki-moon also strongly condemned the attacks and expressed confidence "that Belgium's and Europe's commitment to human rights, democracy and peaceful coexistence will continue to be the true and lasting response to the hatred and violence of which they became a victim today," his spokesman said.
Belgium's interior minister says authorities knew that some kind of extremist act was being prepared in Europe but that they were surprised by the scale of the attacks in Brussels.
Interior Minister Jan Jambon said Tuesday that "it was always possible that more attacks could happen but we never could have imagined something of this scale."
Jambon told RTL television that "we had no information about this, but we know that things were moving in Europe, in different countries, in France, in Germany, here."
He said the Belgian authorities have no information about the planning of "any kind of action in Brussels at this time."
Some of Europe's best-known monuments have been illuminated with Belgium's national colours in a show of solidarity after the attacks in Brussels.
At nightfall Tuesday, the Eiffel Tower in Paris lit up in the black, yellow and red colours of the Belgian flag.
Berlin's landmark Brandenburg Gate, which after the November attacks in Paris was illuminated with the French colours of red, white and blue, also was lit up in Belgian colours. A few blocks away, some people laid flowers and lit candles outside the Belgian Embassy.
And in Italy, Rome's Trevi Fountain joined in the show of Belgium's national colours.
Belgian federal prosecutors say a house search in the Brussels neighbourhood of Schaerbeek has "led to the discovery of an explosive device containing among other things nails."
Investigators also found chemical products and an Islamic State flag.
Their statement said that IS had claimed responsibility for the attacks in Brussels via a press agency but that this information still needs to be verified.
Prosecutors say it's not possible at this stage to establish any links between the attacks Tuesday in Brussels and those in Paris on Nov. 13 that left 130 people dead.
A Belgian prosecutor says police raids are happening around the country after two men "probably" staged suicide bombings at the Brussels airport and a third fled.
Prosecutor Frederic Van Leeuw said Tuesday that the third suspect is actively being sought by police.
At least 31 people were killed and nearly 190 wounded in the two airport bombings and another in the Brussels subway system.
Prime Minister Charles Michel said the country will tighten security at its borders. He declared three days of national mourning after what he says were probably the most tragic attacks the country has seen in peacetime.
Federal police in Belgium have issued a wanted notice for a suspect in the Brussels airport bombing that they are still trying to identify.
A man wearing a thick light-colored jacket with a black hat and glasses is suspected of committing an attack at Zaventem airport on Tuesday morning.
They are urging the public to call them if they recognize the man.
Ralph Usbeck, 55, an electronics technician from Berlin, was checking his baggage for an American Airlines flight to Florida when the first blast struck in Brussels. He assumed it was a training exercise.
He says "seconds later, a much more heavy, heavy detonation happened, some more distance (away) but much more heavy. This was the moment I realized this was a terrorist act."
He says few people appeared worried after the first bomb went off but the second did spark panic and crying amid billows of "dirty dust, like from concrete."
He says "it took a very, very long time till the ambulances came" — maybe 30 minutes.
The British government is warning Britons against all but essential travel to Brussels in the wake of the bomb attacks.
Prime Minister David Cameron's office said the travel advice was being changed in line with the advice issued by Belgium authorities.
Belgium on Tuesday raised its terror threat to the highest level — denoting "a serious and imminent threat" — and told residents to stay where they were after Tuesday's bomb attacks on the city's main airport and a subway train. The city's transit network was shut down for several hours.
Downing St. said a team of British police had been sent to Brussels to help with the investigation into the attacks that have killed at least 31 people and wounded nearly 190.
German Chancellor Angela Merkel has pledged Belgium's prime minister her country's "full solidarity" following the Brussels attacks and says her Cabinet will discuss the bombings on Wednesday.
Merkel spoke with Prime Minister Charles Michel and promised that "we will work in every way with his government and the Belgian security forces to find those responsible for today's crimes, detain and punish them."
Merkel says "our strength lies in our unity, and our free societies will prove to be stronger than terrorism."
Airport security has been boosted across Europe — and even across the Atlantic Ocean following the attacks in Brussels.
Police and aviation officials in the Nordic countries boosted security at major airports in Denmark, Sweden, Finland and Norway.
German Interior Minister Thomas de Maiziere said security measures were increased at "critical infrastructure" in Germany and along its borders with France, Belgium and the Netherlands.
Authorities also stepped up security around New York City even though there was no known link to the Brussels attacks that killed 31 people and left nearly 190 wounded.
The Port Authority Police Department increased security at New York City's three area airports — John F. Kennedy, LaGuardia and Newark Liberty — and bridges, tunnels and the bus terminal. It placed anti-terrorist patrols throughout its trans-Hudson River system and the World Trade Center site. Additional bag checks also were being conducted at PATH stations.
Florence Muls, a spokeswoman for the Brussels Airport, says a third bomb has been neutralized at the airport after two other bombs killed at least 10 people there Tuesday morning.
Muls told The Associated Press the third bomb was dispensed of "with a controlled action" once the chaos of the first explosives had eased somewhat.
Elsewhere in the Belgian capital, anti-bomb squads detonated suspicious objects in at least two locations — the Maelbeek subway station and close to Brussels University a few miles further away. Authorities said those two did not contain explosives.
A U.S. official has told the AP the explosives in Brussels appear sophisticated, and investigators will examine them to see if they bear the same characteristics to those used in the Paris attacks last year.
Russian President Vladimir Putin says the terror attacks in Brussels have underlined the need to pool global efforts for combating terrorism.
Putin spoke in televised remarks Tuesday as he met with visiting Finnish President President Sauli Niinisto.
Putin began by offering condolences to the families of the victims in Brussels. He added "we have repeatedly discussed the issues related to the fight against terrorism, and it's possible to efficiently combat it only by united efforts."
Some other Russian officials and lawmakers have criticized Western reluctance to co-operate with Moscow on fighting terrorism amid the strain in Russia-West ties over the Ukrainian crisis.
The White House says President Barack Obama has expressed his condolences to Belgium and its people during a telephone conversation with Prime Minister Charles Michel following deadly terrorist attacks at the airport and a subway station.
Obama also offered assistance with the investigation and with bringing the perpetrators to justice.
The White House says the president reiterated U.S. support for the people of Belgium, NATO and the European Union. And he pledged the full co-operation by the U.S. in efforts to end terrorism.
Obama placed the call from Havana, where he was closing a historic three-day visit on Tuesday.
The head of the Brussels Airport says the airport will remain closed at least through Wednesday.
Airport CEO Arnaud Feist says two bombs ripped through the airport's departure hall, killing at least 10 people there and injuring scores. Feist said it was still too early to assess the damage to the terminal and indicated the airport could be closed even longer.
He said thousands of passengers and personnel were at the airport during the morning rush hour when the attacks hit Tuesday.
The exact number killed at the airport is still unclear. Regional governor Lodewijk De Witte says there are "more than 10 deaths" there.
European Union leaders are pledging to tackle the terrorism threat with "all necessary means" after attacks on Brussels — the EU capital — that killed at least 31.
The heads of state and government of the 28-nation union said in a statement that Tuesday's attack "only strengthens our resolve to defend European values and tolerance from the attacks of the intolerant."
They pledged to be "united and firm in the fight against hatred, violent extremism and terrorism."
The statement didn't elaborate on possible EU measures in response to the attacks.
The Belgian federal prosecutor's office has made a new plea to the media not to spread any information about the investigation in the wake of the bombing attacks early Tuesday.
Belgian authorities had already made a similar plea during the days following the Nov. 13 Paris attacks when they were certain an attack in Brussels was imminent. It was largely followed by the media.
On Tuesday, the office again asked the media to immediately desist from spreading information from the ongoing investigation.
The Islamic State group claimed responsibility for the attacks in Brussels, saying its extremists opened fire in the airport and "several of them" detonated suicide belts.
The posting in the group's Amaq news agency said another suicide attacker detonated in the metro.
The posting claimed the attack was in response to Belgium's support of the international coalition arrayed against it.
People can start moving around Brussels once more after being told to stay in place for hours after bombing attacks Tuesday morning at the airport and on a subway station.
Peter Mertens of the Belgian crisis centre says "the threat is still real and serious" of more attacks.
But he says air traffic at Brussels' Zaventem airport "remains closed for the day under any circumstance" but people in the Belgian capital can start walking outside again and train stations are reopening.
At least 31 people were killed and nearly 190 wounded Tuesday after bombs went off in Brussels airport.
Florence Muls, the Brussels airport communications manager, is defending the security at the airport.
She tells The Associated Press that the terminal zone is open. That means there are no checks on luggage or passengers at the entry to the terminal — and European rules do not require closing it off.
She says the airport is does not have the ability or the mandate to impose controls at the airport terminal entry.
An Iraqi intelligence official says sources in the Syrian city of Raqqa have told them that the Islamic State group has been planning terrorist attacks in Europe for two months which would "target airports and train stations."
The official tells The Associated Press on Tuesday that Iraqi officials told European countries about the plans "but Brussels was not part of the plans" at the time.
He says IS militants changed the operation and moved it to Brussels "because of the detention of Salah Abdeslam" — the Paris attacks suspect arrested Friday in Brussels.
Another senior Iraqi intelligence official said "Daesh (IS) was behind this operation and it was planned in Raqqa two months ago and there are three suicide attackers who will carry out another attack."
The officials spoke on condition of anonymity since the investigation was ongoing.
— Qassim Abdul-Zahra in Baghdad
A U.S. official says security officials believe at least one suitcase bomb was detonated at Brussels Airport on Tuesday morning.
The official, who wasn't authorized to speak publicly on the early investigations, confirmed a statement by a Brussels official that there is also concrete evidence of one suicide bombing at the airport Tuesday as well.
U.S. intelligence agencies had been on alert for possible attacks since Friday's arrest in Belgium of accused Paris attacks conspirator Salah Abdeslam. But the official said it was unclear if Tuesday's bombings were already planned and set in motion by his or another existing network, or if they were a direct response to Abdeslam's arrest.
The official said the explosives seen in Brussels on Tuesday appear sophisticated. Investigators will examine them to see if they bear the same characteristics as those used in Paris last year.
— Bradley Klapper in Washington.
Pope Francis has condemned the "blind violence" of the Brussels attacks and has offered prayers for the victims, their families and emergency responders.
Francis' secretary of state, Cardinal Pietro Parolin, sent a telegram of condolences Tuesday to the archbishop of Brussels, Mons. Jozef De Kesel.
In it, Francis said he "condemns once again the blind violence that breeds so much suffering and implores the gift of peace from God" for all Belgians.
Nations around Europe are declaring with solidarity with Brussels after three bombing attacks left at least 31 people dead in the Belgian capital.
The French National Assembly opened its session on Tuesday with a minute of silence for the victims. Lawmakers in the Czech parliament in Prague and lawmakers in Spain also held a minute of silence.
Paris Mayor Anne Hidalgo and Belgium's ambassador plan a silent gathering Tuesday evening and the Eiffel Tower will be lit in the colours of the Belgian flag.
In London, the British prime minister's office at Downing Street in London has also raised the Belgian flag in solidarity.
Czech Prime Minister Bohuslav Sobotka has expressed solidarity with the Belgian government and says: "The fight against terrorism is our common fight."
Interior Minister Milan Chovanec says security has been boosted at Prague's international airport, the capital's subway network, at some foreign embassies, other airports and all across the country, including at the Temelin nuclear plant.
Czech President Milos Zeman, who is known for his anti-Muslim rhetoric, says "we underestimate the threat of terrorism linked to the wave of migrants."
No group has claimed responsibility for the three bombings Tuesday morning that killed at least 31 people and wounded nearly 200 in Brussels.
A Belgian TV station is reporting that at least one of the bombs at the Brussels airport contained nails.
Flemish language broadcaster VTM interviewed Marc Decramer of the Gasthuisberg hospital in Leuven, who says the hospital is treating 11 people with serious injuries, three of them in critical condition. Decramer says the wounded have fractures and deep cuts caused by flying glass and nails.
Belgian officials say 31 people were killed Tuesday and 187 wounded in two explosions at the Belgium airport and one at a city subway station.
Passenger Cedric Vanderswalm says a late train and a full elevator at Brussels airport probably saved his life.
The 20-year-old from the coastal Belgian town of Knokke was at the Brussels airport on Tuesday planning to fly to London for his job as an animator.
He says was heading to the airport's departures level but the elevator was full "so I didn't get in. I waited and I was about to step into the elevator when there was a big explosion." He says people started running, dropping their luggage.
He says "if I had taken the previous elevator, I would have been right in the explosion. My train also had a 5 minute delay, so I was lucky."
The explosion coated the left side of his face with soot and dust.
The mayor of Brussels is raising the toll of dead and injured from a subway bombing.
Mayor Yvan Majeur now says at least 20 people have died and 106 people were injured in the attack on the Maelbeek subway station, which is close to the European Union headquarters.
Earlier, another top Belgian official said 11 people were killed and 81 have wounded in twin explosions at the Brussels airport.
So in all, 31 people have been killed and 187 wounded in the three blasts.
A minute of silence has been held outside the Spanish parliament and Madrid's town hall at noon in memory of the victims in Brussels.
The Spanish government says the attacks Tuesday in Brussels show "the most brutal and inhumane side of those who know only the language of violence and terror."
Foreign Minister Jose Manuel Garcia Margallo linked the attacks to the Islamic State armed group. He says previous attacks in Paris claimed by IS militants had shown the assailants acting "like well-co-ordinated and militarily well-structured commandos" instead of lone wolves.
Top Spanish officials were meeting later on the situation but the Interior Ministry said for now Spain is keeping its national security alert at one step below the maximum.
A European security official in contact with Belgian police says least one and possibly two Kalashnikov rifles have been found in the departure lounge at the Brussels airport after the attacks.
The official spoke on condition of anonymity because he was not authorized to speak about the ongoing investigation.
Shiraz Maher, a senior researcher at The International Centre for the Study of Radicalisation and Political Violence in London, calls the presence of guns in these attacks "quite significant."
Maher says this "presents an incredible challenge to continental Europe, where guns are much more freely available as opposed to here in the United Kingdom."
Maher says guns make it "much more difficult to secure soft targets like transport sites."
— Paisley Dodds, Europe correspondent
London police are appealing for images and video footage from Britons who may have witnessed the attacks in Belgium.
The Metropolitan Police say they have "activated an online platform where images and videos can be uploaded which could provide important information for the investigating authorities."
Earlier, British police stepped up security across the country, including transport hubs like London's Heathrow and Gatwick airports.
London Mayor Boris Johnson says the increased police is to reassure the public "rather than because of any intelligence of an attack."
Scotland Yard Assistant Commissioner Mark Rowley says his agency is working closely with Belgium authorities on anti-terror efforts.
Britain's threat level remains at "severe," which means an attack is highly likely. It has been at that level since 2014.
Police in the Netherlands say they have halted an international train from Brussels to Amsterdam at a station just one stop from the Dutch capital's busy Schiphol Airport as a precaution and are searching the train and its passengers.
Local police said on Twitter that Hoofddorp station had been evacuated and will stay closed until the investigation is completed. Passengers were being put up in nearby hotels.
There was no immediate word of any arrests and police did not say what prompted them to stop the train. The incident came just hours after deadly attacks on the Brussels airport and a city subway station.
Photos spread on social media are showing armed police patrolling the Dutch train station.
Hundreds of stranded passengers, some wheeling luggage carts from the Brussels airport, have gathered at a municipal sports hall in nearby town of Zaventem.
Henry Dewespelaere, a 22-year-old butcher, was one of the local volunteers in fluorescent yellow vests compiling lists of the passengers' names and nationalities.
He says the travellers would have the option of being taken to a hotel in Leuven by train. If people elect to stay in Zaventem, he says "we don't know yet what will happen, we're waiting for further instructions."
The Brussels airport was shut down Tuesday after it was hit by two explosions. Another explosion hit a city subway station. In all, 26 people have been killed and over 130 have been wounded in the attacks.
Belgian officials say the casualty toll from three explosions in the capital on Tuesday morning is 26 dead and at least 136 wounded.
Belgian Health Minister Maggie de Block says 11 people are dead and 81 have been injured in twin explosions at the Brussels airport.
A Brussels subway spokesman says 15 people have been killed and 55 were injured in an explosion at the Maelbeek train station.
No one has claimed responsibility for the attacks, which come after a top suspect in the deadly Nov. 13 attacks in Paris was arrested Friday in a massive police raid in Brussels.
The U.S. Embassy in Brussels is recommending that Americans in Belgium stay where they are and avoid public transportation.
The embassy noted Tuesday that with the threat rating in Brussels at its highest alert, attacks can take place with little or no notice. It urged U.S. citizens to monitor media reports, follow instructions from the authorities, and "take the appropriate steps to bolster your personal security."
More than 200 flights to Brussels have been diverted or cancelled after three explosions that authorities are calling terror attacks, according to the flight tracking service Flightradar24.
Scores of people are dead after two explosions hit Brussels airport Tuesday morning and a third hit the city's Maelbeek metro station.
The Brussels airport has been shut down and airport security has been tightened across Europe.
The European Union's top official says he's appalled by the attacks on Brussels' main airport and a metro near the EU's institutions and has offered Europe's support.
EU Council President Donald Tusk says Tuesday "these attacks mark another low by the terrorists in the service of hatred and violence."
He says the EU "will fulfil its role to help Brussels, Belgium and Europe as a whole counter the terror threat which we are all facing."
Staff at the EU institutions near the Maelbeek metro station — where at least 15 people have been killed by a blast — been warned to stay in their offices or at home.
French officials are condemning the Brussels attacks in the strongest terms.
Prime Minister Manuel Valls, speaking after a crisis meeting called by the French president, says "we are at war. We have been subjected for the last few months in Europe to acts of war."
President Francois Hollande says "terrorists struck Brussels but it was Europe that was targeted — and all the world that is concerned."
Hollande also warned that "this war will be long" so sang froid and lucidity are needed.
Paris says it will light the Eiffel Tower in the colours of the Belgian flag. The city's mayor, Anne Hidalgo, described it in a tweet as a measure of "solidarity with Brussels."
German Chancellor Angela Merkel's chief of staff has called for solidarity with Belgium following the Brussels attacks that left scores dead.
Peter Altmaier tweeted Tuesday: "Terrorists will never win."
He added: "Our European values much stronger than hate, violence, terror!"
Russian Foreign Ministry spokeswoman Maria Zakharova says the West's politics of "double standards" have led to terrorist attacks and that frozen diplomatic relations between NATO and Russia have slowed the fight with terrorism.
The Kremlin, meanwhile, has offered its condolences to Belgium and expressed solidarity after the attacks Tuesday that left scores dead.
While Russia and the United States have brokered a fragile peace agreement in Syria, the two countries still disagree on how to tackle terrorist threats posed by the Islamic State group.
Prominent Russian lawmaker Alexei Pushkov also had a jab at Europe and NATO following the Brussels attacks. Pushkov later offered his condolences, but said "it's time for Europe to understand where the genuine threat is coming from and join efforts with Russia."
Facebook has activated its "safety check" system to help people check on friends and loved ones in the aftermath of the attacks in Brussels.
The company says Tuesday the system was put in use within hours of the three explosions at the Brussels airport and a metro station.
It says the system can provide an easy way for people to mark themselves as "safe" after a major disaster or crisis so that people searching for them will know they are unharmed.
The system has been used recently to help people communicate after major floods and earthquakes as well as terrorist attacks.
A Belgian subway official says there are 15 dead, 55 injured in the subway station attack.
Spokesman Guy Sablon gave the toll to The Associated Press after two explosions hit the Brussels airport on Tuesday morning and a third hit the city's Maelbeek metro station.
European Union foreign policy chief Federica Mogherini, fighting back tears, has stopped short a news conference in Jordan after saying that "today is a difficult day," in reference to the Brussels attacks.
Mogherini was wrapping up her opening statement Tuesday at a joint news conference with Jordanian Foreign Minister Nasser Judeh when she was overcome by emotion. When Judeh resumed speaking, she walked over to him, said "sorry" and briefly embraced him. The two then walked off the stage.
Mogherini and Judeh had been speaking for about 16 minutes when the news conference ended abruptly. In her opening remarks, she had talked about the importance of her visit to Jordan, praising the kingdom's stance against militant Islam.
Belgian federal prosecutor Frederic Van Leeuw is calling all three explosions in Brussels "terrorist attacks."
Two of the explosions on Tuesday morning hit Brussels' Zavantem airport and the third struck in the city's Maelbeek metro station. Belgian media report that at least 13 are dead, and authorities are saying there are dead at both sites.
Van Leeuw says "one attack was probably done by a suicide bomber."
Belgian Prime Minister Charles Michel says "what we feared has happened" and says authorities are worried there will be more attacks.
Speaking a news conference in Brussels, Michel says "there are many dead, many injured" from the attacks earlier Tuesday at the airport and a subway station. He says border controls have been reinforced.
Michel says "we realize we face a tragic moment. We have to be calm and show solidarity."
Brussels police spokesman Christian De Coninck says there were deaths at the Maelbeek police station near European Union headquarters.
He says: "There are victims, serious injury, people have died. I have no idea yet on the numbers of injured or dead."
France's top security official said the country is reinforcing security at airports, train stations and metros after Tuesday's attacks in Brussels.
Interior Minister Bernard Cazeneuve said France immediately increased its vigilance after the attacks. France has been on highest alert since the Nov. 13 attacks in Paris that left 130 dead.
Anthony Deloos, an employee of services company Swissport, said the first explosion took place near a counter where customers pay for overweight baggage. He and colleague said second blast was near the Starbucks.
"Twenty meters (yards) from us we heard a big explosion," and shredded paper was flying through the air, Deloos said. He first thought a billboard had fallen down, but a colleague told him to run.
"I jumped into a luggage chute to be safe," he said.
In a statement marked "aanslagen" — terror attacks in Dutch — the prosecutor's office in Brussels has warned people to stay inside until the situation is cleared up.
After a few hours of uncertainty on the explosion during morning rush hour, it was the first official indication that indeed, they were expected to be terror attacks.
Eurostar has suspended high-speed rail service to Brussels-Midi station following the attacks at the airport and a metro station in Belgium
The rail service links London with Brussels and Paris via the Channel Tunnel.
Dutch Prime Minister Mark Rutte says Belgium has "again been hit by cowardly and murderous attacks. Our hearts go out to the victims and next of kin. The Netherlands stands ready to help and support our southern neighbours in any possible way."
Rutte says that "extra alertness is necessary, also in our country. We will take all necessary precautionary measures." Rutte called a meeting Tuesday of his government's Ministerial Crisis Committee to discuss the attacks.
The Dutch anti-terror authority said the country's threat level was unchanged at "substantial." It said extra security measures would be in place at the country's airports and borders.
British airports are increasing security and Prime Minister David Cameron is convening the government's emergency committee after the explosions at Brussels airport and on the city's subway system.
Cameron said Britain would "do everything we can to help."
Britain's official terrorist threat level stands at "severe," the second-highest level on a five-point scale, meaning an attack is highly likely.
Gatwick airport said that "as a result of the terrible incidents in Brussels we have increased our security presence and patrols around the airport." Heathrow said it was working with police to provide a "high-visibility" presence on light of the attacks.
Germany's justice minister says "today is a black day for Europe" following the attacks in Brussels.
Heiko Maas said Tuesday on Twitter that "the horrible events in Brussels affect us all."
He added: "We are steadfastly at the Belgians' side."
French President Francois Hollande is holding an emergency meeting after explosions targeted Brussels airport and a metro station at morning rush hour.
The blasts came days after the arrest of the top suspect in last year's Paris attacks, Salah Abdeslam, in Brussels.
Hollande is meeting with Prime Minister Manuel Valls, Defence Minister Jean-Yves Le Drian and Interior Minister Bernard Cazeneuve.
France remains in a state of emergency after the Nov. 13 attacks, which killed 130 people. Several attackers were also killed.
Russian Transport Minister Maxim Sokolov tells Russian news agencies that authorities will re-evaluate security at Russian airports. In 2011, a suicide bombing at a Moscow airport killed 37 and injured many more.
Zach Mouzoun, who arrived on a flight from Geneva about 10 minutes before the first blast, told France's BFM television that the second louder explosion brought down ceilings and ruptured pipes, mixing water with blood from victims.
"It was atrocious. The ceilings collapsed," he said. "There was blood everywhere, injured people, bags everywhere."
"We were walking in the debris. It was a war scene,"
An Associated Press reporter saw several people with facial injuries following an explosion in a Brussels metro station near European Union headquarters. At least two people were seen being moved on stretchers
Alexandre Brans, 32, who was wiping blood from his face, said: "The metro was leaving Maelbeek station when there was a really loud explosion. It was panic everywhere. There were a lot of people in the metro."
Police say that at least one person was killed when two explosions ripped through the departure hall at Brussels airport.
"One person has died and perhaps there are several more," said a police official who spoke on condition of anonymity because the situation was developing.
The official urged people to stay away from the airport.
Two explosions ripped through Brussels airport Tuesday during the morning rush hour as hundreds of passengers were trying to check in. Airport authorities said the explosions caused several injuries.
Airport spokeswoman Anke Fransen said: "There were two blasts in the departure hall. First aid team are in place for help."
Passengers were led onto the tarmac and the crisis centre urged people not to come to the airport.
The explosions happened only days after the prime suspect in the Paris attacks Salah Abdeslam was arrested in Brussels.
By The Associated Press