A Tibetan rights group says Chinese security forces fired into a crowd of protesters in China's southwestern Sichuan province, killing one man and wounding three others.
The International Campaign for Tibet said the incident took place Thursday in the province's Aba prefecture, when crowds tried to stop security forces from arresting a youth who posted pro-Tibet leaflets.
The incident could not be independently verified, but would be the third such incident this week.
Witnesses say security forces killed at least six protesters Monday and Tuesday in separate incidents in Sichuan, which is home to many ethnic Tibetans. They said at least 60 people were injured.
On Thursday, the elected leader of Tibet's exile community called for a global vigil next month to condemn the killings. Lobsang Sangay described the earlier killings as "gruesome" and "unacceptable."
Many of the protests have been spurred by activists who were posting leaflets declaring self-immolations by Buddhist monks and others would not stop until Tibet is free.
The International Campaign for Tibet said Thursday's incident was sparked by a young man named Tarpa, who posted leaflets which also had his name and photo on them and challenged Chinese police to arrest him if they wanted to.
The U.S. State Department has been urging China to start a dialogue with the Dalai Lama and address long-standing Tibetan grievances.
China seized control of Tibet more than 50 years ago, forcing the Dalai Lama and other Tibetan leaders to flee to northern India. The exile government has operated since then in Dharamsala.