A Tibetan monk set himself on fire in protest today during a prayer festival in a part of western China that erupted in deadly riots a year ago, an activist group said.

The monk started the blaze after walking out of a monastery in Aba county, an ethnic Tibetan area in Sichuan province, carrying a Tibetan flag with a picture of exiled spiritual leader the Dalai Lama, said Matt Whitticase, spokesman for the Free Tibet Campaign.

The monk was surrounded by armed police, three gun shots were heard and he was carried away in a van after falling to the ground, Whitticase said, citing unidentified sources. It was not known whether the monk was dead or alive, he added.

Reuters reached three people by phone in the town outside the Kirti monastery, where the monk had been based, but was unable to obtain confirmation of the protest.

"This is the first incident that I am aware of a Tibetan self-immolating since the late 1990s," Whitticase said. "It is extremely rare."

Tibetans marked their New Year this week and the Kirti monastery, which had been a centre of pro-independence demonstrations last March before a crackdown, was observing the Monlam prayer festival today, Whitticase said.

Next month also marks the 50th anniversary of the exile of the Dalai Lama, following a failed insurrection against China, and there is intense security across Tibet itself and many neighbouring areas with ethnic Tibetans.