China has increased security in Tibet ahead of the second anniversary of ethnic riots in the Himalayan region.
Reports from Tibet's capital, Lhasa, say police and soldiers have been deployed across the city. Authorities also are checking identity papers and searching vehicles heading toward Lhasa.
The group Human Rights Watch says it has reports that some people already have been detained without charges. The rights group urged China Friday to respect the rights to freedom of expression and peaceful assembly for those who want to mark the second anniversary of the March 2008 unrest.
Since those riots, central Chinese authorities have made special efforts to prevent renewed unrest in majority Tibetan regions.
Peaceful protests turned violent on March 14, 2008 after the government sent in troops to disperse crowds.
Beijing says more than 20 people were killed and many others were injured. Shops and government buildings were vandalized.
The government accuses Tibet's exiled spiritual leader, the Dalai Lama, of inciting the riots with the goal of gaining independence for the region. The Dalai Lama denies the accusation and says he is only campaigning for Tibet's cultural autonomy.
Tibet this month also marked the 51st anniversary of a failed uprising against Chinese rule.
In a speech Wednesday marking the (March 10) anniversary of the uprising, the Dalai Lama accused the government in Beijing of trying to deliberately annihilate Buddhism in Tibet. Chinese officials criticized his speech and said it proves that he is intent on dividing China. Some information for this report was provided by bbc , kyodo and aljazeera.