At least 55 people have been arrested for their suspected links to Daesh during counterterrorism operations in Istanbul and Izmir, a police source said on Thursday.

Anti-terror squads conducted simultaneous operations at 12 locations in seven districts of Istanbul apprehending 45 foreigners who were allegedly planning to carry out an attack, the source – who spoke on condition of anonymity due to restrictions on talking to the media –  said.

During the raid, police also seized a number of documents and digital tools.

Separately, police also rounded up 10 Daesh suspects in the western province of Izmir during simultaneous operations in the city.

The arrests came after Izmir Chief Public Prosecutor's Office issued arrest warrants for 11 suspects.

More than 300 people have lost their lives in Daesh-claimed attacks in Turkey so far, where the terror organisation has targeted civilians in suicide bombs, rocket and gun attacks.

Turkish security forces have been involved in a long-running campaign to thwart Daesh attacks.