Selahattin Demirtas (L) and Figen Yuksekdag, co-chairs of the pro-Kurdish Peoples' Democracy Party, address their party members as they start their campaign for Turkey's November 1 parliamentary elections, during a meeting in Ankara October 2, 2015. REUTERS/Umit Bektas/File Photo

ANKARA (Reuters) - Turkish authorities detained nine officials from the country’s main pro-Kurdish opposition party on Saturday, a party official said, a day after the party’s leaders were formally arrested.

The nine officials included the provincial and district heads of the pro-Kurdish opposition Peoples’ Democratic Party (HDP) in the southeastern province of Adana, the official said.

HDP co-leaders Selahattin Demirtas and Figen Yuksekdag were arrested on Friday as part of a terrorism investigation, prompting strong international condemnation of a widening crackdown on dissent under President Tayyip Erdogan.