Dharamsala, Aug 23 (IANS): Chinese security forces used machine guns to quell protests in Tibetan capital Lhasa in March 2008, a human rights watchdog here has said.

"A leaked document provides irrefutable evidence that Chinese security forces killed Tibetans in different localities in Lhasa city during the initial protests in March 2008 that ignited the uprising in large parts of the Tibetan plateau," the Tibetan Centre for Human Rights and Democracy (TCHRD) said.

The document, accessed recently by the TCHRD, provides evidence that the security forces used disproportionate force, including machine guns, to kill Tibetans.

It was written in Chinese by the Lhasa Public Security Bureau based on autopsy reports prepared March 21, 2008, the Tibetan government-in-exile said Friday in a post on its official website quoting the human rights watchdog.

The internal report, titled "Document of the criminal and medical examination department of the Public Security Bureau, Lhasa", contains the list of 22 Tibetans killed by the security forces and autopsy reports of four Tibetans.

Li Wen Zhen and Wang Zhai Shai, both heads of the criminal and medical examination department of the Lhasa Public Security Bureau, performed the autopsy, it said.

China's crackdown on peaceful protests across Tibet in 2008 left over 227 Tibetans dead, said the government-in-exile.

China accused the government-in-exile, based here in Himachal Pradesh, of orchestrating a deadly wave of unrest in Tibet ahead of the Beijing Olympics in 2008.