Airports in the U.S. and around the world increased security after Tuesday night’s suicide bombing attack at Istanbul's Ataturk Airport, where ISIS is suspected of killing at least 41 and injuring hundreds.
The body count was expected to keep climbing in the wake of the attack at one of the world's busiest airports after three suicide bombers opened fire with AK-47s before blowing themselves up as police engaged them. As if to underscore Turkey's determination to carry on in the face of a growing threat, the airport reopened Wednesday, just hours after the dead and some 239 wounded were carried away and glass and debris were cleared.
"The findings of our security forces point at the Daesh organization as the perpetrators of this terror attack," Turkish Prime Minister Binali Yildirim told reporters at the airport, using the Arabic name for ISIS. "Even though the indications suggest Daesh, our investigations are continuing."
The attack bore hallmarks similar to the March 22 coordinated terror attacks in Brussels, in which ISIS operatives killed 32 in coordinated bombings at Zaventem airport and a nearby metro station. ISIS had not taken credit for Tuesday's attacks at Ataturk Airport, and Ankara has battled Kurdish militants as well as ISIS.
But Turkish officials told The Associated Press and Reuters that ISIS was the prime suspect, and the Islamic State released an infographic Wednesday in which it claimed to have "covert" units in Turkey. The infographic, sent out via ISIS' Amaq news agency, was made to commemorate the two-year aiversary of the militants establishing their so-called caliphate in areas of Syria and Iraq.
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 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.
Most of those killed were Turkish, officials said. The 13 foreign travelers killed included five Saudis, two Iraqis and citizens from China, Iran, Jordan, Tunisia, Ukraine and Uzbekistan, Reuters reported.
The assault began when one attacker blew himself up outside the Ataturk terminal, the Haber Turk newspaper reported. Two other terrorists then opened fire at a point where X-ray machines are located.
"He's shooting up, two times, and he's begiing to shoot people like that, like he was walking like a prophet," Otfah Mohamed Abdullah, who witnessed one of the attackers, told AFPTV.
One attacker was shot at while ruing amid fleeing passengers, then blew himself up at an exit. The third attacker went up one level to where the inteational departures terminal is, was shot by police and blew himself up.
A Turkish official told The Associated Press that authorities were going through CCTV footage and eyewitness statements to establish a more detailed timeline of the attack. "It is a jigsaw puzzle" said the official, who spoke on condition of anonymity in line with govement protocol.
Airport surveillance video posted on social media showed the moment of one blast, a huge ball of fire, and passengers fleeing in terror. Another appeared to show an attacker, felled by a gunshot from a security officer, blowing himself up seconds later.
The recent attacks on Turkey, a key partner in the U.S.-led coalition against ISIS and a NATO member, have increased in scale and frequency. They have scared away tourists and hurt the Turkish economy, which relies heavily on tourism.
"If this Islamic State is indeed behind this attack, this would be a declaration of war," Analyst Soner Cagaptay, director of the Turkish Research Program at The Washington Institute, told AFP. "Turkey's vengeance will come down like rain from hell on the Islamic State."
Hundreds of passengers who fled the airport in fear were left sitting on the grass outside. Several ambulances drove back and forth, and security vehicles surrounded the scene.
Adam Keally, from Boston, said he heard gunfire followed by several explosions, then saw people "very badly injured."
Hevin Zini, 12, had just arrived from Duesseldorf, Germany, with her family and was in tears.
"There was blood on the ground," she told the AP. "Everything was blown up to bits... if we had arrived two minutes earlier, it could have been us."
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 AP. "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."
A State Department spokesman told Fox News late Tuesday that Americans in Turkey were being urged to contact family members immediately.
Saudi Arabia's Embassy in Turkey said at least seven Saudis were injured in the attack and all were in stable condition.
U.S. and world leaders immediately offered condolences following the attack.
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 on 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.
Turkey has stepped up controls at airports and land borders and deported thousands of foreign fighters, but has struggled to tackle the threat of ISIS militants while also conducting vast security operations against Kurdish rebels, who have also been blamed for recent deadly attacks.
Turkish airports have security checks at both the entrance of terminal buildings and then later before entry to departure gates.
Istanbul's Ataturk Airport was the 11th busiest airport in the world last year, with 61.8 million passengers, according to Airports Council Inteational. It is also one of the fastest-growing airports in the world, seeing 9.2 percent more passengers last year than in 2014.
Fox News' Catherine Herridge, Matt Dean and Lucas Tomlinson and The Associated Press contributed to this report.