The Dalai Lama has called for an end to the violence in Tibet and rejected accusations by China that he was responsible for the recent unrest.
The exiled spiritual leader said Tibetans needed to live side-by-side with Chinese people.
China says 13 people were killed by rioters in Lhasa. Tibetan exiles say 99 have died in clashes with authorities.
Tibetan activists have released images they say support their claim of heavy casualties and Chinese brutality.
They say the pictures depict protesters killed by Chinese security forces at Kirti Monastery in Sichuan province on Sunday - but the BBC is unable to verify these claims.
A representative of the Chinese embassy in London, Yu Jing, said it was "hard to judge from the pictures" but that if they were accurate, there would be an explanation.
She said some reports suggested the local police station and police officers had been attacked, and that Chinese officials were looking into the claims.
A Tibetan man in Aba, Sichuan province - apparently close to the monastery - who sent his account to the BBC, said he thought 17 people had died in his area, and added "there is tension everywhere".
On Tuesday, a spokesman for the government in exile said 19 people had been shot by Chinese police during ongoing protests by ethnic Tibetans in Gansu province, north of Sichuan.
There have been reports of unrest in other areas and of whole towns being sealed off by the authorities.
But meanwhile the Chinese authorities have released more video footage they say depicts Tibetans rioting in Lhasa at the end of last week.
The protests began on 10 March - the anniversary of the 1959 Tibetan uprising against Chinese rule - and have gradually escalated.
The Dalai Lama spoke in Dharamsala in northern India, where his Free Tibet Movement is based, to reject accusations by Chinese Premier Wen Jiabao of orchestrating the violence in Tibet.
"Violence is against human nature," the Dalai Lama said. "We must not develop anti-Chinese feelings. Whether we like it or not we have to live side-by-side."
The 72-year-old, who in 1989 was awarded the Nobel Peace Prize for his consistent opposition to the use of violence, said that even if "1,000 Tibetans sacrificed their life", this would be "not much help".
He reaffirmed that he wanted autonomy for Tibet within China, but not outright independence.
At the news conference, the Dalai Lama also rejected Chinese accusations that he has personally instigated the protests in Tibet, and repeated his call for an international inquiry into why they took place.
Earlier, Mr Wen said the Dalai Lama's claim of "cultural genocide" in Tibet was "nothing but lies".
Mr Wen defended China's handling of the crisis, accusing protesters of robbery, arson and violence.
"There is ample fact and plenty of evidence proving this incident was organised, premeditated, masterminded and incited by the Dalai clique," he said.
Mr Wen also said the protesters "wanted to incite the sabotage of the Olympic Games in order to achieve their unspeakable goal".
The Games begin in China on 8 August.
Large numbers of police are patrolling the streets of Lhasa.
A Chinese deadline for protesters to surrender passed on Monday and there is no immediate word on the military's actions.
China says Tibet was always part of its territory
Tibet enjoyed long periods of autonomy before 20th century
1950: China launched a military assault
Opposition to Chinese rule led to a bloody uprising in 1959
Tibet's spiritual leader the Dalai Lama fled to India
However, the BBC has received reports from Lhasa of the Chinese authorities conducting house-to-house searches and arresting suspected Tibetan protesters.
The BBC's Daniel Griffiths, who is in western China, said he had seen long convoys of military vehicles heading across the mountains into Tibet.
Police have stopped BBC journalists from entering the village in which the Dalai Lama was born in north-eastern Tibet.
China says Tibet has always been part of its territory but Tibet enjoyed long periods of autonomy before the 20th Century and many Tibetans remain loyal to the Dalai Lama, who fled in 1959.