China’s government regards the vast Himalayan region of Tibet as an integral part of China and is sensitive to expressions of support for the Dalai Lama, who fled into exile in 1959 and who has accused China of stifling Tibetan culture. The Chinese consider the Dalai Lama a subversive advocate of Tibetan independence, although he has said he only wants greater autonomy for Tibet.

Stephanie Brigden, the director of Free Tibet, identified the monk who killed himself as Tsewang Norbu, 29. She said he was protesting what she described as the harsh treatment of Tibetans following the March 16 immolation by a monk from the Kirti monastery in Aba, or Ngaba in Tibetan, in the same region of Sichuan. She said the repression worsened further when Tibetans in Daofu and elsewhere defied a government ban on celebrating the Dalai Lama’s 76th birthday on July 6.

“We’ve basically seen an escalation in the clamping down,” she said in a telephone interview. “It is not just limited to this area.”

In a news release, Ms. Brigden said her group had “grave concerns” about what could happen in Daofu in the aftermath of the monk’s immolation, and at his monastery, Nyitso. She said that telephone and Internet access had been cut and that the group had “received reports that the army has surrounded the monastery.”

The resilient support for the Dalai Lama among China’s five million Tibetans has taken on increased significance with time. The Dalai Lama has said he may choose his own successor, deviating from the practice in which senior lamas identify each Dalai Lama’s reincarnation after his death. In response, Chinese authorities in Beijing have said they have the authority to name the next Dalai Lama. They have been seeking to promote their own handpicked successor, the Panchen Lama, second only to the Dalai Lama in the Tibetan Buddhist hierarchy.