A Tibetan nun set herself on fire in southwestern China at the weekend, a campaign group and a report said, in the latest apparent act of protest against Chinese rule. The self-immolation by the nun, whose name and age were not immediately available, occurred Saturday in Kardze Tibetan Autonomous Prefecture in Sichuan province, according to British-based advocacy organisation Free Tibet and US-funded Radio Free Asia. Kalsang Gyaltsen, a lawmaker in the Tibetan government-in-exile in India, told RFA the woman set herself alight while circumambulating a monastery -- a ritual of Tibetan prayer. "The Tibetans who were at the scene intervened and put out the fire, and sent her to the hospital," Gyaltsen told RFA. The station quoted unnamed sources as saying she set herself on fire to show opposition to Beijing's rule in areas inhabited by Tibetans. Free Tibet said in its report Sunday that communication lines to Bathang county,  where the incident took place, were cut and security measures heightened. At least 125 Tibetans in China have set themselves alight since 2009, according to Free Tibet and RFA. The latest incident is the third this month  after two Tibetans died in Sichuan province on March 16. March is a sensitive month for Tibetans, who live in Qinghai and Sichuan as well as Tibet proper. Their spiritual leader the Dalai Lama fled China on March 10, 1959 following a failed uprising. In March 2008, deadly riots erupted in the Tibetan capital Lhasa and spread to other areas Beijing accuses the Dalai Lama of encouraging self-immolations to further a separatist agenda. China also says its rule has brought social and economic benefits to Tibetans and ended what it claims were feudal abuses of the population. The Dalai Lama, a Nobel Peace laureate who lives in India, has described the self-immolations as acts of desperation that he is powerless to stop. Rights groups call the protests a reaction to Beijing's tight control over Tibetans' rights, including the exercise of religion.