ISTANBUL, Turkey, June 29 (UPI) -- Investigators and intelligence officials suspect that Islamic State militants were responsible for Tuesday's coordinated attack on Turkey's Ataturk Airport, which killed at least 42 people and wounded hundreds more.
One of the officials who believes the terror group, also known as ISIS and ISIL, may have pulled the strings behind the attack is CIA Director John Brennan.
"The despicable attacks at Istanbul's national airport yesterday that killed dozens and injured many more certainly bears the hallmarks of ISIL's depravity," he said.
Although the Turkish government faces several militant opposition groups within its borders, local authorities also believe the Islamic State is responsible for the attack, Turkey's state-owned Anadolu News Agency reported.
Ataturk Airport in Istanbul reopened on Wednesday, hours after three suicide attackers opened fire and detonated explosives at the facility. Officials believe two targeted the international terminal and the other an airport parking lot.
The death toll climbed to 42 on Wednesday, according to hospital sources, after a woman died at an Istanbul hospital. A total of 239 people were wounded in the airport attack, with 128 still hospitalized, officials said.
CBS News reported Wednesday that "chatter" from Islamic State militants had been targeting transportation facilities in Turkey, including Ataturk.
All three suicide bombers arrived at the airport in a taxi, officials said, and the cab's driver has reportedly said they were speaking in a foreign language he did not understand.
One theory is that the attackers may have been Chechen jihadists from Russia, CBS News reported Wednesday, who could have links to the Islamic State. DNA tests are being conducted in an effort to help identify the assailants, officials said.
So far, no group has claimed responsibility for the attack.
Tuesday's attack occurred during the Muslim holy month of Ramadan, and as Turkey announced new foreign policy rapprochements with Russia and Israel.
The attack came two weeks after a police vehicle was targeted in a bomb explosion on Istanbul's central Beyazit district. Seven police officers and four civilians were killed and 36 people wounded.
Video: CBS Evening News/YouTube