By GILLIAN WONG

BEIJING — A respected Tibetan lama went on trial on weapons charges Tuesday as three people were sentenced to lengthy prison terms for deadly arson attacks during last year's rioting in the Tibetan capital.

Phurbu Tsering Rinpoche, who headed a convent in Ganzi, a predominantly Tibetan prefecture in Sichuan province, is accused of illegally possessing weapons, his Beijing-based lawyer Li Fangping told The Associated Press in a phone interview.

Li said the monk was forced into making a confession after a police interrogation that lasted four days and threats that his wife and son would be detained if he did not comply.

The 52-year-old monk could be imprisoned for up to 15 years if found guilty, Li said, adding he was the first senior Buddhist leader to face a serious charge linked to last year's demonstrations.

Rioting that broke out on March 14, 2008, led to the most sustained Tibetan uprising against Chinese rule in decades. Last year's violence in Lhasa killed 22 people, according to Chinese officials.

Prosecutors allege a pistol and more than 100 bullets and cartridges were found under a bed in Phurbu Tsering Rinpoche's living room during a police raid, but the monk has denied the allegation, saying he was framed, Li said.

"The charge is untenable," Li said. "Police didn't ask him about the source of the weapons or check for fingerprints."

The monk also pleaded not guilty to a separate charge of embezzlement involving a home for the elderly he set up, the lawyer said.

Another Chinese court sentenced three people to lengthy prison terms over deadly arson attacks during the riots in Lhasa, state media reported Tuesday.

One was given the death penalty with a two-year reprieve for helping to lead attacks on two clothing stores that killed six people, the official Xinhua News Agency said. Such sentences are is usually commuted to life in prison. Another was sentenced to life in prison and a third given 10 years.

Li said Phurbu Tsering Rinpoche was arrested May 18 last year just days after more than 80 nuns in Ganzi held a demonstration against an official campaign to impose "patriotic re-education" on their convents, in which they were required to denounce Tibet's spiritual leader the Dalai Lama.

The International Campaign for Tibet, an activist group, has described Phurbu Tsering Rinpoche as a "deeply respected local figure known for his work in the community" — including the building of a center for the aged and two clinics — whose detention has aroused deep resentment among local Tibetans.

The court has yet to set a date for its verdict, Li said. Calls to the court rang unanswered late Tuesday.

A rugged, deeply Buddhist region filled with monasteries and nunneries, Ganzi is known for its strong Tibetan identity and has been at the center of dissent for years. It saw some of the most violent protests last spring.

State media says more than 950 people were detained after the rioting and dozens of people sentenced for their part in the protests.

Beijing says the demonstrations were part of a violent campaign by the exiled Tibetan Buddhist leader, the Dalai Lama, and his supporters to throw off Chinese rule in Tibet and sabotage last August's Beijing Olympics.

The Dalai Lama, who fled Tibet fifty years ago amid an uprising against Chinese rule, has denied the charge and says he seeks only significant autonomy for Tibet under continued Chinese rule.

Associated Press writer Christopher Bodeen contributed to this report.