Back up by helicopters, Turkish anti-terror police unit arrested on Tuesday a large number of the outlawed Revolutionary People's Liberation Party-Front (DHKP-C) group in a raid campaign targeting 13 different locations and districts including Sultangazi, Gaziosmanpasa and Bagcilar.

According to police sources, the operation is ongoing and the number of the suspects detained will increase.

A number of banned leaflets, three computers and various data storage units were seized in the clampdown.

Founded in 1978, the DHKP-C is considered a terrorist group by Turkey, the EU and the U.S.