Two Tibetans including a mother of four have set themselves on fire in China in two days, rights groups and media reports said Monday, the latest in a series of such protests against Beijing's rule.

A 33-year-old Tibetan named Kal Kyi burned herself to death in protest against Chinese authorities in southwestern China's Sichuan province on Sunday, Radio Free Asia reported, adding she had four children.

The immolation occurred in Aba, a Tibetan-populated county where there have been a number of similar protests since 2009, according to India-based Tibetan website phayul.com

More than 110 Tibetans have self-immolated since 2009, according to rights groups.

A 43-year-old man named Lhamo Kyab set fire to himself on Monday in the western Chinese province of Gansu, said phayul.com and a spokeswoman for the International Campaign for Tibet, a US-based advocacy group.

It was not clear from reports whether Kyab had survived the blaze, as some protesters have done previously.

Many Tibetans in China accuse the authorities of repressing their religion and eroding their culture as the country's Han ethnic majority increasingly moves into traditionally Tibetan areas.

Tensions erupted in violent protests in March 2008 in the Tibetan capital of Lhasa, which then spread into neighbouring areas.

Beijing rejects criticism of its rule, saying Tibetans enjoy religious freedom and pointing to huge ongoing investment that it says has brought modernisation and a better standard of living to the region.