Osman Baydemir, mayor of Diyarbakir, the largest city of the mainly Kurdish southeast, and one of Turkey's most popular Kurdish politicians, will stand trial if a Diyarbakir court accepts an indictment by a prosecutor seeking a 10-year jail sentence.

The prosecution wants a new trial on charges that Baydemir belongs to the separatist Kurdistan Workers' Party (PKK), blacklisted as a terrorist group by the Turkish government, the European Union and the United States.

Kurdish politicians in Turkey are routinely regarded with suspicion and often seen as instruments of the PKK in its campaign to give self-rule to the Kurds.

Baydemir belongs to the country's main Kurdish party, the Democratic Society Party, which itself is under judicial investigation for alleged links with the rebels.

He has been under investigation since March when he hailed the "courage" of young Kurdish rioters as he tried to reason with them in a bid to end deadly unrest in Diyarbakir that followed the killing of several PKK rebels in clashes with government security forces.

Baydemir said he shared the rioters' grief over the slain rebels and urged them to end violence against the government forces.

The authorities have accused the PKK of orchestrating the riots, which spread from Diyarbakir to other towns in the region and to Istanbul, claiming a total of 16 lives.

Baydemir, 34, has been charged in two other cases, with hearings expected to open soon in Diyarbakir.

In one, he risks up to 10 years in jail along with 55 fellow Kurdish mayors for allegedly supporting the PKK.

The case was opened over a letter they wrote to Danish Prime Minister Anders Fogh Rasmussen, urging him to ignore the Turkish-government's calls to ban a Denmark-based Kurdish television station, which Turkish officials accuse of being a PKK mouthpiece inciting to violence.

In the second case, Baydemir risks one year in jail for allegedly allocating a public ambulance to transport the body of a slain PKK militant.

The PKK has been fighting for Kurdish self-rule in the southeast since 1984, in a conflict that has claimed more than 37,000 lives.