Beijing (dpa) - Chinese police said they shot protesters during violent Tibet-related unrest in the south-western province of Sichuan, the official news agency Xinhua reported Friday, in the first admission by government authorities that guns were used against Tibetan protesters.

Police opened fire in self-defence during unrest Sunday in the town of Aba, where members of China's Tibetan minority live, Xinhua said, citing police sources.

In an initial report, Xinhua said four people were killed but later corrected the story to say four people were injured by the gunshots.

Authorities had previously insisted that Chinese security forces had not used any lethal weapons. The spokesman for China's Foreign Affairs Ministry on Thursday denied that security forces had used guns to quell Tibetan independence protests outside the Tibet Autonomous Region.

"They showed maximum restraint," Qin Gang said when asked about the reaction of paramilitary police to widespread protests in Sichuan, the neighbouring province of Gansu and other Tibetan areas.

"They did not use or take any lethal weapons," Qin told reporters.

However, a source in Aba town told Deutsche Presse-Agentur dpa that 13 Tibetans, including an 8-year-old, were shot dead during clashes March 14 and five more were killed March 15. A Tibetan exile group said troops had shot dead 39 people in Aba prefecture.

The Xinhua report said police fired shots Sunday after demonstrators attacked officers with knives and tried to take away their weapons.

Police first fired warning shots but were attacked again, an official with the local public security bureau said.

"Police were forced to fire in self-defence," the official said, adding that the injured ran away with other protesters.

A police station was burned and police cars were destroyed during the unrest, the report said.

The central government has confirmed only 13 deaths in the demonstrations, apparently all non-Tibetans, during rioting March 14 in the Tibetan capital of Lhasa. It earlier denied opening fire on protesters there.

The India-based Tibetan government in exile said it had confirmed the death of at least 80 people in Lhasa.

Protests by Tibetans in China and other countries began March 10, the 49th anniversary of a failed uprising in Tibet against Chinese rule.