A bomb has exploded at a government building in a town in Tibet's Chamdo prefecture and Chinese security forces have sealed off the area, according to Tibetan sources.
The blast in Dzagyu Karma township comes amid rising protests, including 10 self-immolations this year, against Chinese rule in Tibetan-populated areas.
"In the early dawn hours of Oct. 26, there was an explosion in a local government building," said a member of the India-based Tibetan exile parliament, speaking to RFA on condition of anonymity and citing sources in Tibet.
"No casualties were reported," he said. "This could be because no one stays in the building overnight."
Walls of the building had also been painted with slogans in red calling for independence for Tibet, and leaflets had been scattered in the area, he added.
"Now, police and soldiers have blocked both sides of the bridge near the township, and no one is being allowed to cross the bridge. People going to Chamdo and leaving Chamdo are being stopped," he said.
Reached for comment, a Chamdo government official confirmed the bombing, adding, "No one was hurt."
"The Chamdo county government has already sent police and armed public security forces to the town," he said.
London-based International Campaign for Tibet spokeswoman Kate Saunders also confirmed the bombing, citing three sources in India's hill-town Dharamsala, where Tibet's spiritual leader the Dalai Lama is living in exile.
One source said that all the monks in Karma monastery, located on the eastern bank of the Dzachu River in Chamdo and founded in the twelfth century by the First Karmapa, have been confined inside the monastic compound on suspicion of possible involvement in the blast.
According to the source, authorities have also halted the activities of many Tibetans engaged in the production of Buddhist religious objects in the area, known for the profession.
Chamdo has been described by the Chinese official media as the "front line" of the "patriotic education" campaigns favored by the Chinese Communist Party as a means of preempting nationalist protests in Tibet.
New measures have been introduced over the past few months to counter dissent and demonstrations.
Chinese security forces have stepped up security following 10 self-immolations and other protests this year against Chinese rule.
In Sichuan province's Ngaba prefecture, the Kirti monastery, home of most of the 10 Tibetans who have self-immolated so far this year, has been under siege most of the year by Chinese security forces.
Hundreds of monks have been forcibly removed from Kirti and taken to secret locations for "political education."
Reported by Lobsang Chophel and Lobsang Sherab for RFA's Tibetan service. Translations by Karma Dorjee. Written in English by Parameswaran Ponnudurai and Richard Finney.