Eighteen people including the district mayor of Çatak Municipality in the eastern province of Van were detained on Tuesday as part of a terrorism investigation.

In addition to Çatak Mayor Celalettin Bartu who is from the pro-Kurdish Democratic Regions Party (DBP), Çatak deputy mayors and DBP provincial officials in Van have been detained following police raids in their addresses in the early hours of Tuesday.

Turkey has stepped up its crackdown on Kurdish politicians in recent months. Trustees have been appointed to dozens of municipalities in the country’s predominantly Kurdish Southeast, while Turkish courts in November arrested 10 pro-Kurdish Peoples’ Democratic Party (HDP) deputies including the party’s co-chairs. Two more HDP deputies were also arrested in December, bringing the total number of arrested HDP deputies to 12.

Turkey has also arrested dozens of local Kurdish politicians on terrorism charges.

The developments have attracted widespread criticism from the region and Western countries.

This article originally appeared in Turkish Minute on Jan. 3.