A Tibetan nun died after setting herself on fire in southwest China on Thursday, the official Xinhua news agency said, in the 11th such incident involving Buddhist monks and nuns in the restive region.

The International Campaign for Tibet confirmed the death of the nun, named Qiu Xiang and aged about 35, saying she called for religious freedom and the return of the Dalai Lama, the Tibetan spiritual leader, as she set herself on fire.

London-based rights group Free Tibet also confirmed the latest incident when contacted by AFP.

Xinhua said Qiu set herself alight around 1pm (0500 GMT) in Dawu county, part of Ganzi prefecture in China's Sichuan province, and that local authorities had launched an investigation into the nun's death.

Local police declined to comment when contacted by AFP.

Eight Tibetan Buddhist monks and two nuns have now set themselves alight in Tibetan-inhabited regions of Sichuan since the self-immolation of a young monk at the Kirti monastery in Aba county in March sparked major protests that led to a government clampdown.

At least five monks and two nuns have died in the self-immolations, rights groups have said.

"We heard she called for religious freedom and the return of the Dalai Lama to Tibet," International Campaign for Tibet spokeswoman Kate Saunders said, citing sources in the region.

Tibetans in Ganzi prefecture are "known to be strong in their religious beliefs" and the region "has been very restive for some time, particularly since July", Saunders added.

Many Tibetans in China are angry about what they see as growing domination by the country's majority Han ethnic group.

Most of the suicide attempts have taken place around the Kirti monastery, which is also in Sichuan, and which has become a flashpoint for the mounting anger at the erosion of Tibetan culture.

All but two of the incidents occurred in Aba after Chinese authorities in late August jailed three monks for prison terms ranging from 11 to 13 years for their alleged involvement in the March death in Kirti.

Monks in Aba prefecture -- which borders Ganzi -- told AFP last month that the wave of self-immolations are linked to Beijing's refusal to engage with the Dalai Lama and allow the spiritual leader to return to his Tibetan homeland.

The Dalai Lama, who fled Tibet following a failed uprising against Chinese rule in 1959, founded a government in exile in the northern Indian town of Dharamshala after being offered refuge there.

He remains revered in China's Tibetan areas but is vilified as a "separatist" by China's communist authorities.

The Dalai Lama has long denied he is seeking an independent Tibet, but only desires greater autonomy for his homeland under Chinese rule.