"We have arrested seven members of the illegal Pejak group who had pivotal role in urban unrest," West Azerbaijan province police chief, Hasan Karami, told the Khorasan daily.

He said that during the Iranian New Year holidays in late March, Pejak members killed a policeman and two members of the Basij volunteer militia.

Iran says Pejak is linked to the outlawed Kurdistan Workers' Party (PKK), which has waged a 15-year insurgency against Ankara for self rule in the Turkey's mainly Kurdish southeast.

Reports have said at least 120 Iranian police were killed, and scores injured in major insurgent attacks by Kurds last year, notably by Pejak.

Tehran and Ankara are linked by an accord calling on Iran to fight the PKK and for Turkey to fight the People's Mujahedeen, an outlawed armed Iranian opposition group based in Iraq.

Iran has pointed the finger at international forces in Iraq for the recent unrest in Kurdish and Arab communities in its southwestern provinces that border Iraq.