Backed up by helicopters, police raided addresses in several Istanbul districts in search of members of ISIS, the Kurdistan Workers Party (PKK) and other militant groups, it added. The number arrested was not immediately clear.

The Dogan news agency said that 140 addresses were raided in 26 districts in Istanbul, in an operation involving some 5,000 police.

As well as ISIS and the PKK, the operation targeted suspected members of the PKK’s youth wing the The Patriotic Revolutionary Youth Movement (YDG-H) and the Marxist Revolutionary People’s Liberation Party Front (DHKP-C), Anatolia said.

The raids came after 32 people were killed in a suicide bombing Monday in a Turkish town on the Syrian border, blamed on ISIS.

This sparked an upsurge in violence in Turkey’s Kurdish-dominated southeast, where many accuse the Turkish authorities of collaborating with ISIS, accusations Ankara denies.

Two police were shot dead in southeast Turkey close to the Syrian border on Wednesday, in an attack claimed by the PKK’s military wing which said it wanted to avenge the Suruc bombing.

On Thursday, another policeman was killed in the majority Kurdish city of Diyarbakir.

Meanwhile, YDG-H claimed it had shot dead an alleged former IS fighter in Istanbul late Tuesday.