China admitted for the first time that security forces shot at Tibetan protesters, as the military pushed on Friday with a crackdown on volatile areas amid fears of mass arrests.
The admission comes with Beijing's Communist rulers trying to put the country's best face forward in the run-up to the Olympic Games in August, amid scattered criticism but no serious threats of a boycott to the showpiece event.
But after days of saying that no lethal force was used in quashing the biggest protest against Chinese rule in Tibet in nearly 20 years, state media said late Thursday that police had shot four people in "self-defence".
Tibetan activist groups had previously reported eight people had been confirmed killed in the incident, and possibly 30, and released photos they said were of the bodies of eight victims.
China has repeatedly insisted that the only people to have died in the protests were 13 "innocent civilians" killed by Tibetan rioters last Friday in Tibet's capital, Lhasa.
Tibet's government-in-exile based in India said this week it had confirmed 99 deaths in the Chinese crackdown, but that it was struggling to get more information.
The protests began last week to mark the anniversary of a 1959 uprising against China's rule of the vast Himalayan region, amid widespread anger over what they say has been brutal and repressive Chinese policies.
Communist China annexed Tibet in 1951, after sending in troops to "liberate" the devoutly Buddhist region a year earlier.
The latest unrest has come at a sensitive time for China's rulers, with the Beijing Olympics fewer than five months away, and they have made huge efforts to stop the world from getting an independent view of their crackdown.
China has sealed off Tibet from foreign reporters and tourists, while releasing images and television footage of violent Tibetans.
Authorities have also sought to stop the foreign press from travelling to areas in Sichuan, Gansu and Qinghau provinces where protests have broken out.
However foreign journalists, as well as Tibetan exiles and activist groups, have reported a huge military build-up in Lhasa and the other hotspot areas in recent days.
On Thursday, the last foreign journalist known to be in Lhasa reported that thousands of soldiers were in the streets.
"We saw a big convoy of military vehicles with troops in the back," Georg Blume, a journalist with German newspaper Die Ziet, told AFP shortly after being expelled from Lhasa.
"One convoy was about two kilometres (1.2 miles) long and contained about 200 trucks. Each had 30 soldiers on board so that's about 6,000 military personnel in one convoy."
Chinese authorities announced on Thursday that 24 people had been arrested and 170 had surrendered for their involvement in the Lhasa unrest, following a house-to-house sweep of the city.
Tibetan exiled and activist groups warned the Lhasa crackdown was being repeated throughout the other provinces, and that the number of Tibetans now in custody was likely more than 1,000.
"Over 1,000 Tibetan protesters were arrested, hundreds disappeared and the numbers are rising," the Indian-based Tibetan Centre for Human Rights and Democracy said in a statement.
Nicholas Bequelin, a Hong Kong-based researcher with Human Rights Watch, said it was impossible to determine the exact number of people arrested but said there were many.
"The pattern in previous cases has been mass arrests and filtering of those people who have been arrested," Bequelin told AFP.
"We are concerned about the possibility of people being mistreated in detention. There's an abundance of evidence of torture and ill treatment of Tibetans in Chinese prisons."
After speaking with Chinese Foreign Minister Yang Jiechi on Thursday, US Secretary of State Condoleezza Rice called again for China to exercise restraint, but also said that parties should refrain from violence.
Rice pressed the Chinese government to open a dialogue with Tibet's exiled spiritual leader, the Dalai Lama.
Chinese authorities have repeatedly accused the Dalai Lama, who fled his homeland after the 1959 uprising, of masterminding the latest unrest and given no indication they would talk with him anytime soon. (AFP)
China admits to shooting at Tibetans, military cracks down