The official Xinhua news agency did not give any other details on the Lhasa court ruling in a brief dispatch Tuesday.
Tibet's Indian-based government-in-exile says more than 150 people died in a crackdown by Chinese forces on anti-government protesters and rioters. China blames Tibetan rioters for the deaths of at least 20 people.
China has ruled Tibet for nearly 60 years. The Communist Party says it freed Tibetans from what it calls "the dark ages" of feudal serfdom. But refugees accuse Chinese authorities of discrimination and of trying to dilute Tibetan culture.
Some information for this report provided by AP, AFP and Reuters.