Forty people are trapped on a snow-covered highway 5,000 meters above sea level in southwest China's Tibet autonomous region, rescuers said Wednesday.

Heavy snow had buried a 100-km section of the National Highway No. 219 in Zhongba county in Ngari prefecture since Tuesday, stranding 40 passengers aboard four vehicles, according to Zheng Jinshui, a police officer who was leading a 18-strong rescue team.

The rescuers received a call for help from the trapped at around 3 p.m. Wednesday and were heading for the site, Zheng said.

The temperature at the site was minus 30 degrees Celsius and snow was still falling, he said, adding that traffic police had closed the snow-coated section due to safety concerns.