Tibetans display portraits of people who killed themselves in self-immolation, during a protest in front of the Liberty Square in Taipei in October 2011.

Story highlights

Advocacy group: a 32-year-old woman set herself alight Sunday in front of a monastery

A female middle school student also set herself on fire, according to Free Tibet

This month will mark the f4th anniversary of protest marches by Tibetan monks

CNN  — 

The unrest among Tibetans in western areas of China appeared to take another macabre turn over the weekend with reports that a mother of four and a middle school student died after setting themselves on fire in separate protests against Chinese rule.

The acts – which the Chinese government has not confirmed – would bring the total number of reported self-immolations by Tibetans in China during the past year to more than 20, according to estimates from advocacy groups.

They follow an increase in security measures by the Chinese authorities in the region in response to the unrest of recent months and ahead of the sensitive anniversary of protests by Tibetan monks four years ago that ended in bloodshed.

The mother of four, a 32-year-old woman named Rinchen, set herself alight Sunday in front of Kirti Monastery in the county of Aba, which Tibetans call Ngaba, in Sichuan Province, the Tibetan advocacy group Free Tibet said in a statement.

“A mother of four young children travelled to Ngaba to set fire to herself in the town that has become the heart of both protest and repression in Tibet,” Stephanie Brigden, the director of Free Tibet, said in the statement.

Brigden declined by telephone to specify how the organization, which campaigns against Chinese rule in the Tibetan region, got the information for fear of endangering its sources.

Rinchen’s death was also reported by Radio Free Asia, a nonprofit group funded by the U.S. government. Radio Free Asia cited Kanyak Tsering, a Tibetan monk with connections to Kirti Monastery who lives in Dharamsala, the Indian town where the Tibetan government in exile resides.

An official from Aba County’s politics and law committee office said Monday that the authorities had “heard nothing about any self-immolation this weekend.” He declined to give his name. Calls seeking comment from the local police station in the town of Aba went unanswered.

The other reported self-immolation was carried out Saturday by Tsering Kyi, a female middle school student aged 18 or 19, at a vegetable market in the county of Maqu, or Machu in Tibetan, in Gansu Province, according to Brigden of Free Tibet.

The Chinese authorities closed the market following the act and still hold Tsering Kyi’s body, Brigden said, attributing the information to three unidentified people in the area, including one who said they witnessed the events first hand.

Radio Free Asia also reported the death of a female middle school student in Maqu on Saturday, citing an “exile source” with local contacts.

Local officials in Maqu were not available for comment on the matter Monday.

Chinese state-run media have confirmed that some self-immolations have taken place in the provinces of Sichuan and Qinghai in recent months.

This month will mark the fourth anniversary of protest marches by Tibetan monks in Lhasa that ended violently in 2008.

Tibetans say the situation escalated to violence when Chinese police beat monks who had been protesting peacefully; Chinese authorities claim Tibetans launched attacks on Chinese businesses. Officially the death toll is under 20; Tibetans in exile say the death toll is near 150.

CNN’s Jethro Mullen contributed to this report.