ISTANBUL, Dec. 19 (Xinhua) -- The Turkish police on Wednesday detained at least 19 foreigners in Istanbul for their suspected links to the Islamic State (IS) militant group, local media reported.

Counter-terrorism units launched simultaneous operations in 11 districts across the city to capture the suspects, who were allegedly going to conflict zones and plotting terror attacks in Turkey, the private Demiroren news agency said.

Illegal documents, books and digital materials were seized during the raids, according to press reports.

Over the past years in Turkey, more than 300 people were killed in deadly attacks blamed on the IS.