Police in Istanbul and İzmir conducted a series of raids on Thursday in various parts of the city as part of operations targeting Daesh terrorists, and detained at least 20 suspects following the Brussels-style attacks on Atatürk Airport which killed over 40 people on Tuesday night. The nationality of suicide bombers was also revealed on Thursday.

Reports have said that one of the suicide bombers is from Dagestan region in Russia, while the others are from Uzbekistan and Kyrgyzstan.

According to the Anadolu Agency, police raided 16 addresses in Istanbul's Pendik and Sultanbeyli districts on the Asian side, and Başakşehir district on the European side and detained 13 suspects, four of whom are reportedly foreign nationals.

In the Aegean coastal city of İzmir, police detained at least nine suspects.

Meanwhile, Turkish security forces killed two suspected Daesh terrorists at the border with Syria, when they tried to illegally cross into Turkey and ignored warnings to stop.

According to security sources, the suspects were Syrians who were in contact with Daesh supporters Abu Ali and Mustafa Demir.

One of them was identified as Muhammad Arab, who was wanted by Turkey and listed in intelligence reports as a potential suspect who could carry out suicide attacks in the capital Ankara and southern Adana province.

Turkey strengthened security measures throughout the country following deadly shooting and triple suicide attacks on Istanbul's Atatürk Airport on June 28.