Hundreds of Tibetans have been reportedly detained by Chinese security officers in Lhasa, Tibet's capital, after two Buddhist monks set themselves on fire in protest against China's rule over the Himalayan region last week.
Late on Wednesday, Radio Free Asia cited a source as estimating that about 600 Tibetans had been detained since the Tibetan men set themselves on fire on Sunday in the first major protest in four years against perceived Chinese oppression. One of those men died after the act.
The detentions come amid news that a Tibetan woman had set herself ablaze on Wednesday afternoon in Aba prefecture, in southwestern Sichuan province, according to Tibetan advocacy group Free Tibet and Radio Free Asia.
Al Jazeera's Steve Chao, reporting from Hong Kong, said that the woman was a 33-year-old mother of three young children who died on the spot after the self-immolation in front of a monastery.
"Over the past several years, the Chinese government has tightened restrictions on this ethnic group to the point that many now are barred from celebrating Buddhist holidays," he said.
"Experts predict that over the next few months there will be further restrictions.
"But rather than damper the resistance against Chinese rule, many people say that it has further united the Tibetan group.
"These immolations are seen as a peaceful, albeit a very horrific way, of demonstrating against this oppression."
China has branded the self-immolators "terrorists" and criminals, and has blamed exiled Tibetans and the Dalai Lama, the exiled Tibetan spiritual leader, for inciting them.
China considers the Dalai Lama, who fled into exile in India in 1959 after an abortive uprising against Chinese rule, a separatist.
The Dalai Lama says he merely seeks greater autonomy for his Himalayan homeland.
About 35 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 27 have died.
The number could not be independently confirmed because foreign journalists are barred from entering Tibet.
Hao Peng, head of the Communist Party's Commission for Political and Legal Affairs in the Tibet Autonomous Region, has urged authorities to tighten their grip on the internet and mobile text messaging, reflecting government fears about unrest during a month-long Buddhist festival which started last week.
The move is the latest in a series of measures the government says are intended to maintain stability.
"Hao Peng stressed that ... the trouble caused by the activities of the Dalai clique has persisted, and the situation
for stability maintenance is still complicated and grim," the official Tibet Daily newspaper reported.