DIYARBAKIR, Turkey, Nov 17 (AFP) - Thousands of people gathered in Yuksekova town in Turkey's mainly Kurdish southeast Thursday to bury three people killed in riots that have strained the region and rattled the Ankara government.

The coffins of the victims, killed Tuesday, were wrapped in red, yellow and green cloths -- the traditional Kurdish colors that are also the symbol of separatist Kurdish rebels, television footage showed.

Violent protests have shaken the province of Hakkari since the November 9 bombing of a bookstore in Semdinli town, run by a former Kurdish guerrilla, which is widely blamed on the security forces.

Yuksekova deputy mayor Sukru Ergider told AFP the funerals passed without incident, adding, however, that many were irked by military jets flying at low altitude over the crowd.

Kurdish politicians blamed the three deaths on the security forces, urging an official inquiry into the conduct of the police, who officials say only fired warning shots in the air.

Autopsies revealed that two of the victims were killed by gunfire, while the third was crushed.

Officials said a protestor initially reported dead after clashes in Hakkari city Wednesday was alive though in critical condition.

Another person was shot dead in riots after the bombing in Semdinli when an angry crowd almost lynched three suspects.

One of them, who allegedly hurled the bomb and was later arrested, turned out to be a former Kurdish guerilla working as an informer for the gendarmerie, an army unit policing rural areas.

The two others -- both gendarmerie officers -- were set free, while a third soldier, accused of firing at the crowd, was also arrested.

Weapons and documents, including a sketch of the bookstore and a list of people, including the bookstore owner, were found in a car outside the shop.

Justice Minister Cemil Cicek urged patience Thursday for the completion of the investigation.

"Our citizens should trust the probe," he said. "If people stage those demonstrations because they think the incident will be covered up, they should know that nothing will be covered up."

Tensions have mounted in the southeast since the rebel Kurdistan Workers' Party (PKK) called off a five-year unilateral truce in June 2004, shattering a period of relative calm.

On Thursday, a bomb blamed on the PKK went off on a railway in the province of Van, causing damage to a freight train but no casualties, Anatolia news agency reported.

The Kurdish conflict has claimed some 37,000 lives since 1984 when the PKK, blacklisted as a terrorist group by Ankara as well as the European Union and the United States, took up arms for Kurdish self-rule in the southeast.