Two Tibetans set themselves on fire outside a Buddhist temple in Lhasa, the first of a series of self-immolation protests against Chinese rule over Tibet to take place in the regional capital, Radio Free Asia reported on Monday.
The broadcaster said the two Tibetans were taken away by security forces who quickly cleared the area where the immolations took place on Sunday in front of the Jokhang Temple, a key pilgrimage site and tourist destination in the heart of Lhasa.
The city was "filled with police and paramilitary forces and the situation is very tense" in the wake of the self-immolations, the US government-sponsored broadcaster quoted an unidentified source in Lhasa as saying.
At least 34 Tibetans have set themselves on fire since March 2011 in protest against China's six-decade rule over Tibet, according to Tibetan rights groups. At least 24 have died.
China brands the Dalai Lama, who fled into exile in India in 1959 after an abortive uprising against Chinese rule, as a separatist. The Dalai Lama says he is merely seeking more autonomy for his Himalayan homeland.
Telephone calls to the Tibet Autonomous Region and Lhasa municipal governments were not answered.
"For the Chinese authorities, it has very serious implications and suggests that the movement is spreading among Tibetans," Mr. Barnett told Reuters. "It could lead to an increased severity of restrictions and controls."
Voice of America, another US-backed radio station, reported online that the two Tibetans who set themselves on fire were restaurant workers, not monks.
Only one other self-immolation had been reported in the Tibet Autonomous Region, a province-level administrative area under the central government. The rest occurred in Tibetan-populated areas of other provinces in southwestern China.
The Chinese term for the Jokhang Temple was blocked on Monday on the popular microblogging site Sina Weibo.