China said on Wednesday it was engaged in a "life or death struggle" over Tibet as it announced 105 people had surrendered over an uprising and exiled groups warned hundreds had been detained.
After days of violent protests against Chinese rule over the Himalayan region, China signalled it would step up a controversial campaign to quell the unrest despite intense international scrutiny ahead of the Olympics.
"We are currently in an intensely bloody and fiery struggle with the Dalai Lama clique, a life or death struggle with the enemy," Tibet's Communist Party leader Zhang Qingli said in an editorial in the Tibet Daily on Wednesday.
"As long as we... remain of one heart, turn the masses into a walled city and work together to attack the enemy, then we can safeguard social stability and achieve a full victory in this intense battle against separatism."
While China has insisted it has used no deadly force to quell the unrest, Tibet and other parts of the country that have seen Tibetans protests in recent days remained sealed off to the foreign press to prevent independent reporting.
Tibet's parliament-in-exile said on Monday that "hundreds" of people had been killed in the Chinese crackdown, while activists have released photos of dead Tibetans whom they say were shot by Chinese security forces.
China's official Xinhua news agency said 105 Tibetan "rioters" in Lhasa had surrendered by late Tuesday night, following a midnight Monday deadline in which they were promised leniency if they turned themselves in to authorities.
China has said Tibetan protesters killed 13 "innocent civilians" on Friday last week, the biggest day of protests that began a few days earlier to mark the anniversary of a failed 1959 uprising against Chinese rule.
Tibetan government vice chairman Baema Chilain said the people who gave themselves in to police had been directly involved in "the beating, smashing, looting and arson" on Friday, according to Xinhua.
Exiled groups and rights activists said hundreds, possibly thousands, of Tibetans had been detained and were at risk of torture amid a sweep by Chinese security forces throughout Tibet and the other hotspot areas.
"It seems like there are so many hundreds of arrests at least, possibly thousands, across the country (wider Tibetan region)," Lhadon Tethong, director of Students for a Free Tibet, told AFP.
"We cannot keep up at this point... there is such a flood of information."
Human Rights Watch said in a statement it had unconfirmed reports of hundreds of arrests and warned those in custody were at great risk of being tortured.
"Given the long and well-documented history of torture of political activists by China's security forces there is every reason to fear for the safety of those recently detained," said Brad Adams, Human Rights Watch's Asia director.
"Only by giving access to independent monitors can China give the world some confidence that detainees are not being tortured or mistreated."
A male official with the public security bureau in Lhasa would not comment on the surrenders or reported arrests on Wednesday and told AFP not to call back.
The Dalai Lama, Tibet's spiritual leader who fled his homeland after the 1959 uprising, held a press conference from his base in northern India on Tuesday to defend himself against Chinese accusations that groups aligned to him were responsible for the unrest.
The Nobel Peace laureate, 72, said Tibetans and Chinese needed to live "side by side," urged his people not to resort to violence and reiterated he was not trying to wrest the remote region from Beijing's control.
"We must build good relations with the Chinese," he said from Dharamshala.
But in the article printed on Wednesday, Tibet chief Zhang made it clear what the government thought of the Dalai Lama.
"The Dalai Lama is a wolf wrapped in a robe, a monster with human face and animal's heart," Zhang said.
China's officially annexed Tibet in 1951, a year after sending troops in to "liberate" the region.