BREAKING: At least 36 people were killed and 147 more were injured when three suspected ISIS suicide bombers attacked Istanbul's main inteational airport Tuesday night, Turkish officials said.

Prime Minister Binali Yildirim confirmed the death toll from the blasts at Istanbul Ataturk Airport. Earlier, Justice Minister Bekir Bozdag confirmed that 147 people had been wounded in the attacks.

The Associated Press initially quoted a senior Turkish official as saying that close to 50 people had already died. However, the news agency later said that the official told them the figure was expected to rise to close to 50.

A Turkish official told Reuters that the "vast majority" of victims were Turkish, but some foreigners were also affected.

There was no immediate claim of responsibility, but the same senior Turkish official told AP that initial indications suggested ISIS were behind the attack. According to Reuters, a police source also told the Dogan News Agency, "ISIS is behind the attack."

"The findings of our security forces point at the Daesh organization as the perpetrators of this terror attack," Yildirim told reporters at the airport, using the Arabic name for ISIS. "Even though the indications suggest Daesh, our investigations are continuing."

A U.S. govement official told Fox News that the attack fits the profile of ISIS, which has stepped up its targeting of Turkey. The official said that ISIS tends to attack inteationally known targets with an economic impact, such as an airport, while the Kurdish terror group PKK generally targets Turkish military and law enforcement.

The attack occurred one day before the two-year aiversary of ISIS declaring a caliphate across large swathes of Iraq and Syria, led by Abu Bakr al-Baghdadi.

Yildrim told reporters that the initial investigation indicated that all three attackers opened fire before blowing themselves up. He added that the terrorists took a taxi to the airport before launching their attack.

Another Turkish official told AP two of the attackers detonated explosives at the entrance of the inteational arrivals terminal after police fired at them, while a third blew himself up in the parking lot. Security video appeared to show one of the attackers ruing through the terminal with a weapon. In the footage, the attacker falls down, possibly after being shot, then detonated his suicide vest.

When asked whether a fourth attacker might have escaped, Yildirim said authorities have made no such assessment but are considering every possibility.

The U.S. official told Fox News that the apparent coordination among the suicide bombers also points to an ISIS operation, as does its resemblance to the March bombings in Brussels, which killed 32 people.

Turkish airports have security checks at the entrance of terminal buildings and then again before entry to departure gates.

Police sealed off the terminal and flights were prevented from taking off or landing for several hours. Early Wednesday, Yildirim aounced that air traffic to and from Ataturk Airport had resumed.

The Federal Aviation Administration (FAA) aounced late Tuesday that all flights between Istanbul and the U.S. had been halted until further notice. The Port Authority of New York and New Jersey aounced Tuesday that extra officers would be deployed to New York City's JFK and LaGuardia airports, as well as Newark Liberty Inteational Airport.

A law enforcement source told Fox News that there were no immediate plans for additional security in so-called "sterile zones", or areas where passengers have already gone through checkpoints, at U.S. airports. The official said any decision to add security outside sterile zones would be made by state or local law enforcment.

Some passengers were kept in Ataturk Airport for over two hours after the explosions before the terminal was evacuated. Hundreds spilled out on to the sidewalk with suitcases in their hands or stacked on trollies.

Two South African tourists, Paul and Susie Roos from Cape Town, were at the airport and due to fly home at the time of the explosions.

"We came up from the arrivals to the departures, up the escalator when we heard these shots going off," Paul Roos told the Associated Press. "There was this guy going roaming around, he was dressed in black and he had a handgun."

Veysel Allay, who was waiting for a friend in the arrivals terminal, told the Daily Telegraph, "A man ran up and ripped open his jacket, showing a bomb vest. I ran before he did anything."

Jim Hyong Lee of South Korea told the Telegraph he and his family were checking in for a flight home when "we heard gunshots."

"I grabbed my family and ran," Lee said. "Someone waved us into the prayer room and hid us there until the police came."

Roads around the airport were sealed off for regular traffic after the attack and several ambulances could be seen driving back and forth.

In the U.S., President Obama was briefed about the attack by Lisa Monaco, his homeland security and counterterrorism adviser. A statement from the White House Tuesday condemned the attack "in the strongest possible terms."

"We remain steadfast in our support for Turkey, our NATO Ally and partner, along with all of our friends and allies around the world, as we continue to confront the threat of terrorism," the statement said.

Attoey General Loretta Lynch said in a statement that the Justice Department and FBI "have offered assistance to our Turkish counterparts as needed." A law enforcement source told Fox News that FBI assets had not been sent to Istanbul as of Tuesday evening.

Republican presidential candidate Donald Trump's campaign released a statement saying, "The terrorist threat has never been greater ... We must take steps now to protect America from terrorists, and do everything in our power to improve our security to keep America safe."

Democratic presidential candidate Hillary Clinton released a statement saying the attack "only strengthens our resolve to defeat the forces of terrorism and radical jihadism around the world. And it reminds us that the United States caot retreat."

Ataturk Airport is the largest in Turkey and the third busiest in Europe behind London's Heathrow Airport and Paris' Charles de Gaulle. More than 60 million passengers went through the hub in 2015. It is also one of the fastest-growing airports in the world, seeing 9.2 percent more passengers last year than in 2014.

Turkey has been the target of recent terror attacks by ISIS extremists, as well as Kurdish nationalist groups. Earlier this month, a car bomb targeted a bus carrying riot police in Istanbul, killing 11 people and injuring 36 others.

The attacks have increased in scale and frequency, scaring off tourists and hurting the Turkish economy, which relies heavily on tourism revenues.

Fox News' Catherine Herridge, Matt Dean and The Associated Press contributed to this report.