Four Tibetans set themselves on fire Wednesday to protest Chinese rule ahead, hours before a key gathering of Communist Party's leaders in Beijing.
At least two of the protesters died, said the Tibetan government in exile in India, citing sources on the ground.
Rights group Free Tibet says the four self-immolations represent the highest number of such incidents in one day.
Hours later, Chinese leaders gathered Thursday for the Communist Party's 18th National Congress in Beijing. The days-long gathering will usher in a new set of leaders of the world's most populous nation.
After a decade in power, Chinese President Hu Jintao is expected to hand over the party's top job to Vice President Xi Jinping.
One of the dead Wednesday was a 15-year-old monk, who set himself alight with two other monks in a majority Tibetan region of Sichuan Province, said the Tibetan Centre for Human Rights and Democracy. They cried "freedom for Tibet" and for the "return of the Dalai Lama." The other two monks, both 16, were hospitalized.
The boys were from the same monastery in Ngaba county, where CNN has reported a number of such incidents in the past.
In a separate incident, a 23-year-old woman died after setting herself on fire in Rebkong county (Tongren county in Chinese), which is in the Qinghai Province, said exile Tibetan government spokesman Penpa Tsering in Dharamsala, India.
Self-immolation is a common form of protest for Tibetans who want genuine autonomy from China and accuse Beijing of repression.
China began a gradual occupation of Tibet in the 1950's. Tibet's leader, the Dalai Lama, fled for India in 1959 after a failed uprising, and many ethnic Tibetans followed him.
Beijing rejects accusations of oppression of Tibetans, saying that under its rule, living standards have greatly improved for the Tibetan people. It makes centuries-old historical claims on the region.