Chinese repression has lead to the self-immolations of nearly two dozen Tibetans and deadly clashes with Chinese authorities, the head of Tibet's government-in-exile said Wednesday.

"Tibetans inside Tibet are giving up their lives. They're saying, 'I choose to die,'" Lobsang Sangay, the leader of the self-declared exile government, said after an afternoon prayer vigil at the main temple in this Indian hill town.

Around 20 Tibetans, many of them monks or nuns, have set themselves on fire over the past year, mostly in ethnic Tibetan areas of China's Sichuan province. Many had chanted for Tibetan freedom and the return of the Dalai Lama to Tibet before lighting themselves on fire.

In recent weeks, Sichuan has also seen bloody clashes between Tibetans and China's forces.

Sangay said convoys of Chinese security forces had been seen moving toward Tibet in recent days, ahead of the Tibetan New Year, on Feb. 22, and the March anniversary of the failed 1959 uprising that sent the Dalai Lama, the Tibetan spiritual leader, fleeing into exile.

"If the Chinese government think that the Tibet issue can be solved through violence, intimidation, then it's not going to happen, because the Tibetan spirit is strong," he said.

On Tuesday, China vowed to crack down on the unrest, and accused overseas activist groups and the Dalai Lama of fomenting the violence.

"We believe that this is a case of a handful of criminals illegally gathering and smashing and looting," Foreign Ministry spokesman Liu Weimin said in a routine briefing.

It has been the region's most violent period since 2008, when deadly rioting spread from Tibet's capital, Lhasa. China responded then by flooding the area with troops and closing Tibetan regions entirely to foreigners for about a year.

Earlier Wednesday, hundreds of Tibetan activists marched through the streets of New Delhi, calling for freedom for their homeland and decrying Chinese rule.

The government-in-exile had called for vigils to be held Wednesday amid the immolations and clashes.