A Washington-based advocacy group says Chinese authorities have surrounded a monastery in Sichuan province, where hundreds of Tibetan monks marched in defiance of Chinese rule.
The International Campaign for Tibet says the monks are likely under lock down, following their protest in the town of Ngaba (Chinese: Aba) Sunday.
The group's sources in Sichuan say Buddhist monks from the Sey monastery demonstrated after Chinese authorities barred them from observing a traditional prayer festival.
In the same town Friday, a Tibetan monk set himself on fire while holding the banned Tibetan flag and a picture of the Dalai Lama, Tibet's exiled spiritual leader.
Activist groups say police shot the monk while he was burning, but state media say authorities rejected the charge.
Chinese authorities have increased security in Tibetan communities ahead of the March 10th, 50th anniversary of the failed Tibetan uprising against Chinese rule. Last year, pro-independence demonstrations commemorating the 1959 uprising led to a deadly police crackdown.
China published a paper Monday on the situation in Tibet before and after 1959.
It says before Chinese rule, the region was a feudal serfdom where most people suffered poverty, oppression and exploitation. The paper asserts that after 1959, the Chinese government launched a vigorous democratic reform to overthrow that system and liberate about one million serfs and slaves.
Critics say China has discriminated against Tibetans and tried to dilute their Buddhist culture since taking over the area in 1951.