A Tibetan human rights group has condemned death sentences passed by a Chinese court on two ethnic Tibetans found guilty of bomb attacks in the south west of China.

The Tibetan Centre for Human Rights and Democracy, based in India, said the convicted men had been falsely accused and asked the United Nations to intervene.

Earlier this week, the court found the men guilty of three separate attacks, one of which killed a bystander.

Chinese media said the men were also found guilty of illegally possessing guns and of promoting Tibetan separatism.

One of those convicted has had his sentence suspended for two years. Correspondents say such sentences are usually commuted to life imprisonment.

Concerns expressed

A statement by the Tibetan Centre for Human Rights and Democracy said it was "gravely concerned" for the fate of the two men.

"This tightening of repression comes at a time when the Chinese Government is hell bent on branding political activities with acts of terrorism following the attacks on the United States," it added.

China has long accused Tibetan pro-independence activists of a campaign of violence against Chinese targets.

But the BBC's Rupert Wingfield-Hayes, in Beijing, says details of actual incidents rarely get reported.

The two ethnic Tibetans were arrested in April this year, shortly after a bomb went off in the centre of Chengdu, the capital of south-west China's Sichuan province.

Guilty verdict

On Monday, a court in Sichuan found them guilty of that bombing and of two earlier attacks in towns in the far west of the province.

The earlier attacks are reported to have killed one person and injured a number of others.

Both of the men are reported to come from the town of Ganzi, in the far west part of Sichuan bordering Tibet.

The area has a majority ethnic-Tibetan population and has long been a hotbed of pro-Tibetan independence activity.

The town of Ganzi has faced repeated crackdowns by Chinese police trying to root out pro-independence activists.

Western Sichuan was originally known as Cham and was historically part of Tibet.

After the Communists came to power in China in 1949, they amalgamated Cham into Sichuan province.

In 1951, China's People's Liberation Army invaded and occupied the rest of Tibet.