Tibetan exiles and Chinese authorities have released separate details of recent violence in a Tibetan community in the western Chinese province of Qinghai.

The Indian-based Tibetan Center for Human Rights and Democracy and Chinese state media reported on violence in Darlag (Chinese: Dari) County.

China's official Xinhua news agency says the county police chief, a Tibetan, was shot dead Monday while pursuing the ringleader of a local riot that happened last month. Xinhua says the alleged ringleader was killed when police returned fire.

The Tibetan Center for Human Rights and Democracy says a Tibetan nomad was shot by security forces Monday. The center says Chinese authorities responded to last month's protests by dispatching troops to the area and arresting hundreds of Tibetans.

None of these details could be independently confirmed.

Tibetan exiles reported protests in Darlag County last month, but Tuesday's Xinhua report appears to be the first official acknowledgment of unrest in the area.

Human Rights Watch Wednesday said China's trials of 30 Tibetans sentenced Tuesday were held behind closed doors and without meaningful legal defense.

A court in Tibet Tuesday gave the Tibetans sentences from three years to life for their alleged roles in riots in the Tibetan capital on March 14.

China says 18 civilians and one police officer died after several days of rare peaceful protests in Lhasa turned violent. It is difficult to verify the numbers because China has barred reporters from Lhasa since shortly after the unrest occurred.

Tibet's Indian-based government-in-exile said Tuesday that it now estimates at least 203 Tibetans were killed in a crackdown by Chinese forces on protesters in Tibet and neighboring provinces.