ISTANBUL, Turkey, June 30 (UPI) -- Turkish officials said the three suicide attackers who targeted Istanbul Ataturk Airport on Tuesday were from Russia, Uzbekistan and Kyrgyzstan.
Turkish police said they arrested 13 people in connection to the airport gun and bomb attack that left at least 44 dead and hundreds injured.
Police, in 16 raids across Istanbul, detained the suspects Thursday. The police department's anti-terror branch is continuing its search for three other suspects in Turkey's most populated city. Another nine people were arrested in the coastal city of Izmir, although it is not clear if they are related to the airport attack.
Officials have blamed the terror group Islamic State, also known as ISIS, ISIL and Daesh, for the Tuesday attack on the airport that left some 239 injured, but there has been no official confirmation from the group. Prime Minister Binali Yildirim said the investigation is ongoing.
There has also been speculation the Kurdish Freedom Falcons, or TAK, an offshoot of the Kurdistan Worker's Party, or PKK, is behind the attack. TAK claimed responsibility for other attacks in Turkey, including one on June 7 that killed seven police officers and four civilians in Istanbul.
Istanbul Ataturk Airport, Europe's third busiest airport with 61.8 million passengers annually, reopened Wednesday following the attack by three suicide bombers. Officials said two of the attackers targeted the international terminal and the other a parking lot.
The death toll of the airport attack grew to 44 on Thursday, with a 3-year-old boy -- one of the attack's youngest victims -- dying a day after his 25-year-old mother.
The known victims are mostly Turkish, with six Saudis, three Palestinians, two Iraqis, one Tunisian, one Chinese, one Iranian, one Ukrainian, one Jordanian and one person from Uzbekistan, Turkish officials said.