BEIJING — Chinese police officers opened fire on Tibetan protesters this week in a Tibetan area of southwest China, injuring at least 10 people, according to reports late Wednesday by the International Campaign for Tibet, an advocacy group, and Radio Free Asia, which is financed by the United States government.

The shootings took place on Tuesday after Tibetans had gathered to protest the detention the previous day of a respected village leader, known as Wangdak, who had insisted to local officials that Tibetans be allowed to hold a traditional prayer ceremony before a horse festival.

The reports, citing Tibetans in exile, said the police fired tear gas and live ammunition. Wangdak’s son and brother were among those injured, Radio Free Asia reported.

The violence took place in Ganzi Prefecture in Sichuan Province, known to Tibetans as Kardze. The prefecture has been the site of previous violent clashes, including one during a Tibetan uprising in 2008 in which police officers fired on hundreds of protesters. A person answering the telephone at one police station in the prefecture declined to comment.