The police action in Xiahe quieted the town as cars were cleared from the streets and people hurried past armed guards. Residents said they did not know what was happening.

A court officer confirmed those on trial participated in the March demonstrations, in which hundreds of monks marched through town, but declined to specify the number of defendants or their sentences.

Foreign visitors have been barred from the region for much of the past seven months, as authorities scoured monasteries and communities for uprising participants, detaining undisclosed numbers. A month ago the prohibition was lifted in Xiahe even as many other Tibetan areas remain closed.

Across the Xiahe region, Tibetans displayed robust devotion to the Dalai Lama and a strong resentment of the security China has imposed.

In Hezuo, a city set in the folds of a valley, Tibetans congregated around the towering 14-story fortress-like temple to a Tibetan saint. Many worshippers were under 50, having lived their entire lives under Communist Party rule.

At a prayer hall, two portraits of the Dalai Lama - always discouraged and sometimes outright banned by the government - were tacked to a shrine cluttered with reliquaries, paintings and photos of other revered teachers.