Turkish police say they have detained 28 people in simultaneous raids across six provinces in connection with probes into an outlawed Kurdish rebel group.

The National Police Department said Tuesday police conducted raids against Kurdistan Communities Union in Sanliurfa, Diyarbakir, Istanbul, Eskisehir, Mus and Ankara. The detainees include Fatma Izol, head of the Sanliurfa branch of the pro-Kurdish Peace and Democracy Party.

Also Tuesday, five Kurdish rebels were killed in a clash with security forces in Turkey's predominantly Kurdish southeast. The clash took place near the town of Tatvan in Bitlis province.

The Kurdish Communities Union is seen by authorities in Ankara as the political wing of the outlawed Kurdistan Workers Party, or PKK.

Tens of thousands of people have been killed since Kurdish rebels began fighting for autonomy in southeastern Turkey in 1984.

The PKK, founded in 1974, is considered a terrorist group by the European Union and the United States, which has supplied military hardware to Turkey to help fight the decades-long insurgency.