Turkish security forces arrested 51 suspects linked to PKK terrorist organization, a security official said Tuesday.

In a counterterrorism operation, police units in coordination with the National Intelligence Organization's (MİT) regional directorate conducted raids in five districts of western Izmir province.

The official, who asked not to be named due to restrictions on talking to the media, said documents and digital equipment of the terrorist organization, as well as a shotgun were seized in the operation.

The operation is in progress as a total of 65 arrest warrants were issued by Izmir's Chief Public Prosecutor's Office.

The PKK — listed as a terrorist organization by the U.S. and EU as well as Turkey — resumed its armed campaign in July 2015. Since then, it has killed more than 1,200 Turkish security personnel and civilians, including women and children.