A top human rights group says the news that a Tibetan Buddhist nun set herself on fire and died shows a “new level of desperation” against Chinese policies in the region.

An Amnesty International official, Sam Zarifi, said Tuesday Chinese authorities should heed the demands of Tibetans to freely practice their religion and enjoy their culture. Instead, he said China has resorted to a “heavy handed” response that he said can further fuel resentments.

Zarifi called for the immediate release of Tibetans imprisoned for protesting Chinese policies.

The Tibetan exile network, known as Free Tibet, reported that the nun, 20-year-old Tenzin Wangmo, died Monday after lighting herself on fire in Sichuan province near the Tibetan border.

The London-based group said she was the ninth Tibetan, and first woman, to set herself on fire this year.

Last week, the U.S. State Department voiced concern about the self-immolations, and what it called the clear anger and frustration the trend represents. The United States has repeatedly urged China to respect Tibet's unique religious and cultural identity.

China routinely rejects such warnings, calling them an interference in its internal affairs.