China and Nepal have each increased security in advance of Tuesday's 50th anniversary of a Tibetan uprising against Chinese rule.
Officials in Tibet have deployed extra police. Authorities say they are taking action to prevent any possible protests by supporters of exiled Tibetan spiritual leader the Dalai Lama.
Nepal has increased police patrols along the border with Tibet to stop any attempt by Tibetan exiles to cross into Chinese-ruled territory.
China's central government accuses the Dalai Lama of inciting activists to seek independence for Tibet. The Dalai Lama says he is only campaigning for Tibet's cultural autonomy.
Peaceful protests in Tibet's capital last March turned violent after the government sent in troops to disperse crowds.