Beijing - Leaders of China's Tibet Autonmous Region have vowed to go ahead with the Olympic torch relay through the region despite what he described as the threat of "sabotage activities" by supporters of the exiled Dalai Lama, state media said on Sunday.

Zhang Qingli, head of the regional branch of China's ruling Communist Party, told a meeting to plan the torch relay on Saturday that "grave challenges remain ahead, as the Dalai clique is plotting new sabotage activities," the official Xinhua news agency said.

Zhang urged "all relevant departments to spare no efforts in preparing for the torch relay to ward off any possible mishap," the agency said.

He said social order in Lhasa and other parts of Tibet was "back to normal" after independence protests and rioting in mid-March.

US-based Radio Free Asia on Saturday said new violence had erupted in the south-western province of Sichuan and left up to 15 people dead after police opened fire on Tibetan protesters on Thursday night.

The broadcaster listed 11 Tibetans identified by local sources as having died during a clash in the Kardze, or Garze, area of Sichuan.

Xinhua quoted a local official as saying police had fired "warning shots" to stop a violent protest but had exercised restraint in quelling a "riot" outside government offices.

The agency said one official was seriously injured in the violence but reported no deaths or injuries to protesters.

Radio Free Asia said the police fired at a crowd of several hundred monks and lay Tibetans who were demanding the release of two detained monks from Kardze's Tongkor monastery.

Dozens of people were injured and many were unaccounted for after the clash, it said.

The Chinese government on Saturday said it had launched a campaign for all party members and officials to "play an active role in maintaining social stability with more loyalty" and spread the message in rural areas, businesses, schools and other organizations.

A party circular urged local governments to "learn from last month's riot in Lhasa," the capital of the Autonomous Region, and "increase anti-secession education among party members and officials at the grassroot level," the agency said.

The clash in Kardze was the latest of dozens of pro-independence demonstrations and unrest in Tibetan areas since March 10, when protests began to mark the 49th anniversary of a failed Tibetan uprising against Chinese rule.

The protests escalated into rioting on March 14 in Lhasa.

The Chinese government has said 19 people were killed in the violence in Lhasa but the Tibetan government-in-exile said about 140 people have been killed, most of them Tibetans shot by Chinese police. (dpa)