NEW DELHI -- They waded through Himalayan snowdrifts and climbed ice-covered rocky terrain for 17 days, cold, hungry and exhausted. Then came the shooting.

As 75 Tibetan refugees were making a secret trek across the border into Nepal on Sept. 30, moving in single file across a mountain slope near the 5,790-metre-high Nanpa La Pass, Chinese border guards opened fire, killing at least one person.

Yesterday, for the first time, witnesses to the shooting stepped forward to describe what happened

"There was no warning of any kind. The bullets were so close I could hear them whizzing past," Thubten Tsering, a Tibetan monk, told journalists in New Delhi. "We scattered and ran."

Mr. Tsering is among 41 refugees who managed to reach India after the shooting. The refugees said 32 others, including nine children, were taken into custody by the guards.

"We don't know where they are or what happened to them," said Mr. Tsering, his chapped cheeks and exhausted face still bearing the scars of the ordeal.

Dolma Palkyid, a 15-year-old novice nun, was a close friend of Kelsang Nortso, a 25-year-old Buddhist nun who was killed immediately in the shooting.

"I had walked ahead and we got separated. Then the shooting took place and we fled. It was four days later that I heard Kelsang was the one who was shot," she said, speaking haltingly and tearfully, through an interpreter.

Once in India, the friends were hoping to join another Buddhist nunnery together, said the teenager, dressed in a traditional ankle-length gown.

Every year, more than 2,500 Tibetan refugees attempt the arduous trek, said Tenzing Norgay of the Tibetan Centre for Human Rights and Democracy, which arranged the news conference yesterday.

"This is the first time that the world has seen evidence of what Tibetans are subjected to by the Chinese," he said.

"Kelsang's death cannot go in vain. We will use this incident and the video footage to bring international pressure on China and press for Tibetan freedom."

Unable to get passports, many Tibetans trek over Himalayan passes to reach Nepal and then India, where the Dalai Lama, the spiritual leader of Tibetan Buddhists, lives in exile. Reports of arrests and ill-treatment by Chinese authorities are common.

What brought the Sept. 30 shooting to international attention is that mountaineers, on an expedition, saw the gunfire and filmed it.

Footage of the incident, shot by a Romanian cameraman, has sparked an international outcry.

The video, released by Romania's Pro TV, shows a distant figure that its narrator says is a Chinese border guard firing a rifle and a separate scene of a person in a line of figures walking through the snow, then falling to the ground. An unidentified man near the camera can be heard saying in English, "They are shooting them like . . . like dogs."

The Chinese government, in a report released two weeks ago by the official Xinhua news agency, said the border guards fired in self-defence after clashing with about 70 people trying to leave the country illegally. It said one person died in the shooting and another died later.

Asked about his life in a monastery in Tibet, where the monks are under the constant watch of Chinese security forces and under pressure to denounce the Dalai Lama, Mr. Tsering said: "It was stifling. Being a monk who has taken a vow to live by the faith, we were always under threat from the Chinese political authorities," he said.

There have been instances of refugees being shot at by border guards in the past, but this was the first time in recent years that troops killed any, said Mr. Norgay.