Turkish President Recep Tayyip Erdogan has accused the leader of the pro-Kurdish opposition party of "provocation and treachery" for comments supporting self-rule for Kurds in Turkey's southeast.

Erdogan was speaking to reporters Tuesday, a day after prosecutors in Ankara launched a probe into Peoples' Democratic Party leader Selahattin Demirtas. He voiced support on Sunday for a declaration calling for autonomy, issued at the end of a two-day congress by Kurdish groups.

Separate investigations were also launched into Demirtas and other Kurdish politicians in the southeastern city of Diyarbakir for backing the declaration.

The legal moves come amid heightened tensions over violence between the security forces and Kurdish militants in three urban districts.

Erdogan said Demirtas and others would be "taught a lesson" by the people and the law.