Turkish police on Thursday took 17 PKK suspects into custody in an operation targeting the terrorist organization's urban structure in Istanbul, a security source told Anadolu Agency.

The operation was carried out early Thursday in ten districts of Istanbul, including Beyoğlu, Bahçelievler, Gaziosmanpaşa, Arnavutköy, the source said on condition of anonymity due to restrictions on speaking to the media.

Several homes in these districts had been identified prior to the raids and the 17 people were taken to an Istanbul police station on suspicion of "being members of the PKK terrorist organization, recruiting and holding an illegal protest."

Special operation forces and helicopters took part in the police operation, the source said.

Police also searched the Peoples' Democratic Party's (HDP) office in Beyoğlu district, which allegedly host suspects involved in illegal protests.

Police confiscated one walkie-talkie, a radio jammer as wells many organizational documents.

Numerous arrests have been carried out across Turkey since a July 20, 2015 suicide bombing killed dozens of people in Suruc near the Syrian border.

Most of the suspects detained have alleged links to terrorist organizations such as PKK/KCK, YDG-H (PKK youth wing), Daesh as well as far-left Revolutionary People's Liberation Party-Front (DHKP-C) .

The PKK -- listed as a terrorist organization by Turkey, the U.S. and EU -- resumed its 30-year armed campaign against the Turkish state in July 2015.

Since then, more than 600 security personnel have been martyred and more than 7,000 PKK terrorists have been killed.