The unrest broke in Diyarbakir, the largest city of the Kurdish-majority region, as some 5,000 people took to the streets for the funeral of the four rebels from the separatist Kurdistan Workers' Party (PKK).

One plainclothes policeman was stabbed and three others were beaten as demonstrators attacked their van, smashing its windows, after the vehicle got stuck amidst the simmering crowd.

Police fired shots in the air and sprayed the crowd with pressurized water to rescue their colleagues, an AFP reporter witnessed.

"Revenge, revenge!" the mourners chanted as they marched to a cemetery outside Diyarbakir, with the four coffins carried on shoulders and wrapped in PKK flags.

The dead were among seven PKK rebels whom the army killed in two-day clashes in mountains in the province of Tunceli last week.

Following the burials, some 200 people -- mostly youths with their faces wrapped in scarves -- hurled petrol bombs, firecrackers and stones at public buildings.

The security forces used tear gas and water cannons to disperse the group after they attempted to march to the local headquarters of the governing Justice and Development Party.

At least two protestors and a journalist were injured in the melee.

Funerals of PKK militants in Turkey routinely turn into demonstrations of Kurdish militancy and are often marred by violence.

The PKK, listed as a terrorist group by Ankara and much of the international community, took up arms for self-rule in the southeast in 1984, sparking a conflict that has claimed some 45,000 lives.