China's official Xinhua news agency said overnight that police shot and wounded four protesters this week in a heavily ethnic Tibetan part of the province, where protests broke out after anti-Chinese riots in neighbouring Tibet last Friday.

The unrest has alarmed China, keen to put its best face forward leading up to the Aug. 8-24 Olympic Games in Beijing.

Tensions remain high in Tibet, Sichuan and other areas where the government has poured in troops.

Kangding, a heavily Tibetan town in Sichuan that acts as a gateway to the restive region, was crowded with troops, some on patrol, some loudly practising martial arts moves in the town square.

Students at the local Tibetan-language school were locked in unless they had special permission to leave. Drivers said they were unwilling to travel into tense mountain towns.

"I'm in this to make money, but no matter how much you pay me I won't go that way," one Kangding driver said.

Having initially said four protesters were shot dead in Sichuan, Xinhua amended its account and said they were wounded and that the police had fired weapons only to defend themselves.

But two residents of Aba prefecture, where the rioting started on Sunday, told Reuters they believed several died when the protesters attacked a police station and government offices, burnt cars and attacked officials. Anti-riot troops then moved in.

They said police had detained many men suspected of rioting.

"Everyone here believes that our people died, maybe 10 or more," said one ethnic Tibetan resident who had previously told Reuters of the clash before Xinhua reported it.

"I'm not a supporter of violence and I oppose attacking people just because they're Han," he said, referring to the country's majority Han Chinese population. "But I believe Tibetans also died. They are not telling facts."

"I'M SURE PEOPLE DIED”

Another Tibetan man in the Aba county town where the rioting erupted said he hid inside his home during the riot.

"I'm sure people died. We all know," he said in a brief telephone conversation. "We don't dare go out. They are arresting many people after what happened."

Both residents asked not to be named, fearing punishment for talking to reporters. Other residents refused to say anything.

Troops and anti-riot police have poured into Tibet and surrounding regions to secure the area from more protests.

Roadblocks and vehicle checks have been imposed to restrict travel and keep out foreign journalists, making it impossible to check the conflicting accounts.

Radio Free Asia, a U.S.-funded broadcaster, said on Thursday up to 2,000 Buddhist monks and laypeople continued to protest in Huangnan Prefecture, Sichuan. The report could not be verified.

Authorities said they had arrested dozens of people involved in the Tibet protests. The Tibet Daily reported on Friday that more "wanted" notices were issued the previous day and three suspects had been captured.

More than 170 rioters have handed themselves in, the report said, also offering a phone number for locals to inform on suspected protesters in return for secrecy and rewards.

China's response to last week's violence -- which it says was orchestrated by the Dalai Lama, the exiled Tibetan Buddhist leader -- has sparked international criticism and clouded preparations for the Olympics.

In a phone call with Chinese counterpart Yang Jiechi, U.S. Secretary of State Condoleezza Rice urged China to show restraint towards protesters. But Yang told her the Dalai Lama, the exiled Tibetan Buddhist leader, was to blame for the riots.

"They attempted to exert pressure on the Chinese government, disturb the 2008 Beijing Olympics and sabotage China's social stability and harmony," Yang told her, Xinhua reported.

China says 13 "innocent civilians" died in anti-Chinese riots last week in Tibet's capital, Lhasa, after police broke up earlier peaceful protests led by monks. Exiled Tibetans say as many as 100 Tibetans have died.