An 18-year-old Tibetan Buddhist nun set herself on fire late Saturday in China's troubled southwestern Sichuan province, and later died of her injuries.

An activist group, Free Tibet, issued a statement Sunday identifying the nun as Tenzin Choedon, who shouted slogans of protest against the Chinese government before setting herself on fire.

Tibetan activists said Chinese security forces moved in quickly after the incident, took the injured nun away, and sealed off her nunnery in Aba county, east of Tibet.

Choedon's death brings to at least 19 the number of Tibetans who have set themselves on fire in the past year. Activists say at least 12 Tibetans are believed to have died from their injuries.

Recent months have seen an upsurge in anti-Chinese protests in Tibetan areas of China, the worst since 2008.

The Chinese government accuses the Dalai Lama, Tibet's exiled spiritual leader, and overseas organizations such as the London-based Free Tibet movement of instigating the unrest.