ANKARA, Turkey – Turkish police detained 29 suspected Islamic State group militants in the capital, Ankara, on Friday, some of whom allegedly were preparing to carry out attacks during New Year’s celebrations, the state-run news agency reported.

Some 500 police officers took part in simultaneous raids to detain the suspects, many of them foreign nationals, Anadolu Agency reported. Police had warrants to detain 17 other suspects.

Materials seized by police during the raids indicated that some of the suspects had staked out locations and made preparations for possible attacks on New Year’s Eve, the report said.

There was no immediate information on the foreigners’ nationalities.

Turkey has suffered a series of deadly attacks blamed on IS militants, including a New Year’s attack at an Istanbul nightclub by a gunman that killed 39 people.

The country is stepping up security measures ahead of this weekend’s celebrations, including cancelling several large-scale New Year’s Eve street parties in Istanbul. Turkey’s police chief said 275,000 police officers would be on duty.

On Thursday, police in the northwestern province of Bursa detained 38 IS suspects in similar raids, including several Syrian nationals.