ISTANBUL — Three suspected ISIS suicide bombers who killed 43 people in a gun and bomb attack at Istanbul's main airport this week were Russian, Uzbek and Kyrgyz nationals, a Turkish government official said on Thursday.

Turkey's state-run news agency said that the police have detained over 22 people in connection to the deadly attack, while local reports said police had received advanced warning some three weeks before the attack.

The three bombers, who Turkish officials have identified as ISIS loyalists, opened fire to create panic outside, before two of them got inside the terminal building and blew themselves up. The third detonated his explosives at the entrance.

The government official gave no further details beyond confirming the attackers' nationalities and declined to be named because details of the investigation have not yet been released. He added that "extensive soft-tissue" damage had complicated efforts to identify the attackers. "A medical team is working around the clock to conclude the identification process," he told journalists.

Turkish Interior Minister Efkan Ala said the identity and nationality of one of the bombers had been determined but did not comment further.

The pro-government Yeni Safak newspaper said the Russian bomber was from Dagestan, which borders Chechnya, where Moscow has led two wars against separatists and religious militants since the Soviet Union collapsed in 1991.

Turkey's Hurriyet newspaper named him as Osman Vadinov and said he had come from Raqqa, the heart of ISIS-controlled territory in Syria. The Russian interior ministry said it was checking information about Vadinov.

A spokesman for Kyrgyzstan's state security service said it was investigating, while the Uzbek security service had no immediate comment.

Anadolu Agency said the three foreign nationals are among the group of suspects detained in Istanbul on Thursday. According to Anadolu, the police conducted simultaneous raids at 16 locations in the city, while an additional raid in Izmir saw another 9 arrested.

Prior warning

Turkish intelligence warned about a potential attack by ISIS in Istanbul about three weeks before the city’s airport was hit by the deadly attack, a senior Turkish journalist from Doğan TV was quoted as saying by the local paper Hurriyet.

“Intelligence units sent a warning letter to the top of the state and all its institutions in early June, around 20 days ago, about Istanbul,” the report said.

Turkey's state-run news agency reported that nine suspects linked to ISIS were detained during a large-scale police operation in the coastal city of Izmir and that security forces had killed two suspected ISIS militants at the border with Syria.

Private NTV television said Thursday the two Syrian nationals "were neutralized" after they ignored security forces warnings, but provided no further details. It was not immediately clear if they were trying to cross illegally into Turkey.

NTV, without citing any sources, said one of the two militants was wanted by Turkey on suspicion that he would carry out suicide attacks in the capital Ankara or in the southern city of Adana.