A court in Tibet has sentenced two people to death over riots in Lhasa last year, China's state media said Wednesday, the harshest sentences yet reported over the deadly unrest.

The first group of foreign tourists had arrived in Tibet since the Himalayan region was sealed off last month for the sensitive anniversary of a failed uprising, state media reported.

About 20 people attacked a government building in a Tibetan area in western China after a man accused of supporting separatism went missing, a state news agency reported Sunday.

Assailants threw a bomb into a newly built police station in a Tibetan area in western China, a police official said Tuesday amid heightened tensions and security during a volatile month. No injuries were reported.

Nobel Peace Prize winners, human rights activists and such celebrities as Harrison Ford and Gwyneth Paltrow are urging China to “stop naming, blaming and verbally abusing” the Dalai Lama.

China warned the West not to “put its fingers into” Tibet as the restive region, under heavy security and shut off from the outside world, marked on Saturday the anniversary of last year's deadly riots in Lhasa.

Armored troop carriers and tour buses packed with police roll along the winding mountain roads. Internet service is dead in some places.

China Saturday accused the Dalai Lama of seeking to carve out a “Greater Tibet” and warned other countries to shun contact with him just days before a sensitive anniversary in the tense region.

Tibet's governor insisted Thursday that his region is stable and will remain so ahead of a sensitive anniversary marking communist rule that last year sparked anti-government protests and riots.

He is a “living Buddha” with an iPod, the 23-year-old possible successor to the Dalai Lama who may bridge the gap between Tibet's elder leaders and both an alienated Tibetan youth and a suspicious China.