Turkey's state-run news agency says a chief prosecutor has launched an investigation into pro-Kurdish opposition leader Selahattin Demirtas for comments supporting self-rule for Kurds in Turkey's southeast.

Anadolu Agency said Monday the Ankara chief prosecutor's office is investigating whether Demirtas' words amount to sedition and crimes committed against Turkey's constitutional order.

Kurdish groups, including Demirtas' Peoples' Democratic Party, called for self-rule following a meeting in the Kurdish city of Diyarbakir on Sunday.

In a speech on Sunday, Demirtas supported the groups' declaration, saying his party adheres to the principle of self-rule.

The prosecutor's move comes amid heightened tensions in the southeast and stepped up military operations against Kurdish rebels in three districts which officials say has killed more than 210 militants.