The sergeants, dressed in civilian clothes, were walking in the centre of the town of Yuksekova when they were shot from behind, the report said, adding that police had launched a hunt for the perpetrators.

The incident ocurred as violence flared in the southeast over the past week following a decision by Turkey's electoral board to bar seven prominent Kurdish-backed candidates from running in general elections on June 12.

On Thursday, the board reversed its ruling for six of the candidates, among them iconic Kurdish activist Leyla Zana, in a move that notably quelled Kurdish anger, but smaller demonstrations continued Sunday to protest the killing of a young man in the earlier clashes.

In the town of Bismil, youths hurled stones and petrol bombs at a government building after Zana visited the family of the protestor, who was killed in pitched battles with the police there Wednesday, Anatolia reported.

Police used tear gas and water cannons to disperse the demonstrators.

There was similar unrest in some other towns in the region, including nearby Batman, where police detained some 30 people after a demonstration led by a Kurdish member of the outgoing parliament turned violent, the agency said.

Turkey's southeast has been the theatre of a bloody insurgency led by the separatist Kurdistan Workers' Party that has claimed some 45,000 lives since the rebels took up arms in 1984.