ANKARA - Turkish police detained 111 Islamic State suspects in a vast anti-terror operation in the capital Ankara on Thursday, the latest round-ups in a widening crackdown against the extremist group.

A total of 1,500 police officers took part in the raids across the Turkish capital after authorities issued arrest warrants for 245 suspects, state-run news agency Anadolu said.

The raids took place at 250 addresses where documents and digital material were found, the agency said, without giving further details.

In the western city of Bursa, 27 suspects including Syrians were also detained in anti-IS raids, Anadolu said.

Turkey has been hit by a series of attacks blamed on IS militants in the past two years, including the killing of 39 people in an elite Istanbul nightclub over the New Year by Uzbekistan-born Abdulgadir Masharipov.

He has previously confessed to the attack and will go on trial in Istanbul on December 11.

The group began to target Turkey from late 2015 onwards after Ankara allowed the US military to conduct air strikes on IS targets in Syria via Turkey’s southern Incirlik air base from August 2015.

Tensions remain high despite a lull in attacks since January and Turkish police have conducted raids almost daily against IS cells across the country.

Another four IS suspects were detained in the central province of Kayseri on Wednesday and last week, 11 Iraqis were arrested in the northern province of Cankiri accused of links to IS.

Last month dozens of suspects from the group were detained across the country including 49 alleged members of IS in Ankara, some of whom were suspected of planning an attack.

Between October 22 and November 1, the general security directorate said 283 IS suspects had been detained including 187 foreigners across 25 cities. And according to the interior ministry, around 450 suspects were detained accused of helping or being in contact with IS in October.

Turkey stepped up its fight against IS in recent years after it faced criticism from its Western allies for not doing enough to fight the extremist group.

In August 2016, Ankara launched a cross-border operation in northern Syria dubbed “Euphrates Shield” supporting Syrian opposition fighters to clear its frontier of IS. The operation was successfully completed in March this year.

And in another fight against militants, Turkish forces entered northwest Syria’s largely militant-controlled Idlib province to establish a “de-escalation zone” as part of efforts to end the over six-year Syrian conflict.

Idlib has for the last few months been controlled by Hayat Tahrir al-Sham (HTS), a group led by Al-Qaeda’s former Syria affiliate.