A policeman and a school employee were injured in a melee in Batman city when an unidentified person opened fire as police used tear gas and water cannons to disperse demonstrators hurling stones and petrol bombs, Anatolia news agency reported.

The policeman was hit by three bullets, it said.

In nearby Bismil, an estimated 30,000 people marched at the funeral of a protestor killed in clashes the previous day, chanting slogans in favour of the separatist Kurdistan Workers' Party (PKK), which is fighting for self-rule in the mainly Kurdish southeast.

The mourners carried the coffin, wrapped in PKK flags, on their shoulders as masked youths shouting "Revenge, revenge!" escorted the procession.

The crowd was led by prominent Kurdish politicians, including one who was among the seven candidates declared ineligible to run in the June 12 parliamentary elections.

Unrest broke out as militant youths, marching back to the city centre, hurled Molotov cocktails and stones at the security forces, who responded with pepper gas and pressurised water.

There were similar scenes of violence in other towns across the southeast, while, in Ankara, electoral officials reviewed the appeals of the rejected candidates and the president appealed for peace.

The unrest threatens to mar electioneering ahead of the polls and deepen Turkey's ethnic conflict, which has claimed some 45,000 lives since the PKK took up arms for Kurdish self-rule in 1984.

Citing past convictions and legal technicalities, the Higher Electoral Board (YSK) Monday disqualified seven candidates backed by Turkey's main Kurdish party, the Peace and Democracy Party (BDP), setting the scene for violent protests across the country.

In a signal that it will reverse its decision for at least some applicants, the YSK has asked them to present additional papers.

President Abdullah Gul raised hope Thursday that the disqualified candidates would be reinstated.

"Nothing can be resolved through violence," Anatolia news agency quoted Gul as saying.

"It turned out the documents were incomplete. Since they have been completed now, there should be no problem," he added.

The disqualifications deepened frustration among the Kurds at a time when their parties already face legal hurdles and many activists remain in jail despite a series of reforms broadening Kurdish rights.

Among those barred was iconic Kurdish activist Leyla Zana, winner of the European Parliament's human rights award who has spent 10 years behind bars.

The BDP fielded them as independents to circumvent a 10-percent electoral threshold for parties to enter parliament.

An autopsy report, seen by AFP Thursday, said the 21-year-old protestor in Bismil was killed by a bullet that pierced his left arm and chest.

There was no official word on who fired the fatal shot, but witnesses said police used first plastic bullets and then live rounds against the demonstrators.

Officials said police had responded to an "intensive" hail of petrol bombs, firecrackers and stones, and announced a judicial probe into the killing.

Enraged youths torched the Bismil office of the ruling Justice and Development Party Wednesday night, while a bus driver in Diyarbakir was critically injured when his vehicle caught fire from a petrol bomb.

Meanwhile, three PKK militants were killed and another arrested in fighting with the army in Kahramanmaras province, Anatolia reported Thursday.