The Dalai Lama says Chinese rule in Tibet has at times been "hell on earth."
The Tibetan spiritual leader is set to mark his 50 years in exile on Tuesday by demanding "meaningful autonomy" for his homeland.
About 10,000 Tibetans from around the world have travelled to hear their leader speak from the main Buddhist temple in Dharamsala, a hill town in north India where a government-in-exile is based.
Tibet is under a security clampdown aimed at stifling protest against Chinese rule.
Armed police say they do not expect unrest but are ready to "deal with any situation."
On Monday, President Hu Jintao warned that China would not relax its control of the region which Mao Zedong's forces took in 1950.