Police opened fire and wounded four rioters "in self-defense" during Sunday's unrest that rocked the Tibetan-inhabited Aba county of Sichuan province, police sources told the Xinhua News Agency yesterday.

Rioters burnt down the police station in the Aba township, attacked police with knives and tried to wrestle away their weapons, an official with the local public security bureau said.

Police fired warning shots, but the rioters did not stop and continued attacking officers, he said.

"Police were forced to fire in self-defense," the official said.

Amid the chaos, the injured attackers ran away with the rest of the mob, and police are now trying to locate them, he said.

The rioters destroyed 15 police vehicles and more than 20 pieces of office equipment, he said.

In Lhasa, the local municipal people's procuratorate on Wednesday released arrest warrants for 24 people involved in the riots there last Friday, an official said yesterday.

The suspects are accused of having endangered national security and committing serious criminal offenses, Xie Yanjun, the deputy procurator, said.

The riot "disturbed social order and jeopardized people's lives and property, and the procuratorate will carry out its duty based on fact and the law," Xie said.

(Xinhua News Agency March 21, 2008)