The European Union's foreign policy chief has expressed concern over the detention of 12 pro-Kurdish politicians by Turkish authorities over their refusal to testify in ongoing terror-related investigations, the Associated Press reports.

Friday, November 4's overnight detentions included People's Democratic Party co-chairs Selahattin Demirtas and Figen Yuksekdag.

EU commissioner for foreign affairs Federica Mogherini wrote on Twitter: "Extremely worried for arrest of Demirtas & other HDP MPs. In contact w/ authorities Called EU ambassadors meeting in Ankara."

Mogherini had also criticized last month the detention of the co-mayors of Turkey's largest predominantly Kurdish city, Diyarbakir, issuing a statement calling on Turkey to resume Kurdish peace efforts saying "a political solution is the only viable option."