Two ethnic Tibetan men set themselves on fire together in southwest China to protest Beijing's rule, causing clashes between residents and security forces, rights groups said on Tuesday.

A monk and former monk set themselves alight Monday in Aba town in Sichuan province, sparking a protest that authorities quelled by beating demonstrators with batons, Free Tibet and the International Campaign for Tibet said.

Additional security forces have been deployed to Aba, the site of several such self-immolations and attempts, said London-based Free Tibet.

One man, whose name was given as Lungtok, died and the other, Tashi, was taken to hospital with severe injuries, it said in a statement.

Nearly 50 people have set themselves on fire in recent months in Tibetan-inhabited areas of China in protest at repressive government policies, according to Free Tibet.

Officials from the Aba police and government, reached by telephone, denied knowledge of the latest incident.

Ethnic Tibetans in Tibet and surrounding regions have long-resented Chinese rule, saying it has curbed their religious freedom and diluted their culture through an influx of Han Chinese, the country's main ethnic group.

China counters that Tibetans enjoy religious freedom and have enjoyed improved living standards thanks to China's economic expansion.

The Tibetan capital Lhasa saw violent anti-Chinese government protests in 2008 that later spread to other areas inhabited by Tibetans. Authorities have kept the city under tight security since then.