Turkish police launched a series of raids in the southern province of Adana early on Sunday and arrested a number of people accused of being members of Islamic State (ISIS), state-run Anadolu news agency reported.

Police also seized documents and 500 grams of explosive material, Anadalu said.

The detained were suspected of kidnapping politicians, bureaucrats and organising attacks against police officers and targetting strategically significant places, according to the news agency.

Turkey was one of the principal routes for foreign fighters trying to join ISIS at the height of the group’s self-declared “caliphate.”

There are an estimated 10,000 ISIS fighters in camps and prisons run by U.S.-backed Syrian Democratic Forces (SDF) across northeastern Syria.

Ankara considers the SDF, spearheaded by the People’s Protection Units (YPG), as an extension of the outlawed Kurdistan Workers’ Party (PKK), an armed group that has been at war in Turkey for over three decades, and has launched offensives against the group. (Agency report)