The series of blasts rocked Europe's third largest airport Tuesday.
Suicide attackers at Istanbul's main airport in Turkey left 42 dead and more than 230 injured Tuesday night.
Twelve hours after the attacks at Ataturk Airport, no group had claimed responsibility but two U.S. counterterrorism officials said the Islamic State was at the top of the list of suspects, Reuters reported Wednesday.
"This attack, targeting innocent people is a vile, planned terrorist act," Prime Minister Binali Yildirim said Wednesday morning.
Read: 911 Logs Reveal Horror in Orlando Club: 'My Caller is No Longer Responding, Just... Moaning'
Using the Arabic name for ISIS, he said: "The findings of our security forces point at the Daesh organization as the perpetrators of this terror attack. Even though the indications suggest Daesh, our investigations are continuing."
U.S. Secretary of State John Kerry, speaking from Aspen, Colorado, Tuesday, said: "We are still collecting information and trying to ascertain what happened and who did it."
The blasts rocked Turkey, which is part of the U.S.-led coalition against the Islamic State, around 9.50 p.m. local time Tuesday. Surveillance footage taken inside the airport — Europe's third largest — shows people fleeing before a large, fiery blast is seen.
One attacker used an automatic rifle to open fire in the departures hall, according to reports, while footage showed one of the attackers being shot — apparently by a police officer — before blowing himself up.
All three suicide bombers detonated their bombs near the arrivals hall, which is a floor below, according to reports.
Read: Brussels Bomber Left Suicide Note: 'I Don't Know What to Do'
South African Judy Favish, who had been traveling from Ireland, told CBS that she had just checked in when she heard an explosion and gunfire. She fled to a cafeteria, where she stayed for more than an hour.
"Coming out ... there was blood everywhere," she said. "One of the little rooms had been shattered. It was horrible. It was just horrible — chaos and blood and people running around and anxious worried, and it was just horrible."
The blasts blew out ceiling panels, shattered windows and left people on the ground. But by Wednesday morning, cleanup crews were working in the terminal and flights had resumed.
Authorities, who are now working through footage and witness statements, said that 13 foreigners, including three dual-nationals, were among the dead.
Watch: Counterterrorism Expert Calls For Security Screenings Outside Airports
