The snow-slide struck part of the west-to-east natural gas pipeline project in Xinjiang, where the workers were building a tunnel near Huocheng County, the Xinhua news agency reported on Friday.

Xinhua said 12 workers were trapped, including four who were later found dead. But the region's own official news website (http://www.tianshan.net) reported early on Friday that 20 were missing and one confirmed dead.

Dozens of rescuers struggled through snow drifts of more than 4 metres to reach the remote scene, in hill country, the Xinjiang report said.

Largely Muslim Xinjiang endures long, harsh winters, and temperatures at the disaster site were below freezing. 'The rescue work is extremely tough,' said Xinhua. -- REUTERS