A landslide has engulfed a gold mining area in Tibet, burying 83 workers believed to have been asleep, according to Chinese state media.
About 2m cubic metres of mud, rock and debris swept through the area on Saturday as the workers were resting, covering about 4km (1.5 miles), China Central Television said.
The official Xinhua news agency said the workers in Lhasa's Maizhokunggar county worked for a subsidiary of China National Gold, a state-owned enterprise and the country's largest gold producer.
The disaster is likely to inflame critics of Chinese rule in Tibet who say Beijing's interests are driven by the region's mineral wealth and strategic position and come at the expense of the delicate ecosystem and Tibetans' Buddhist culture and traditional way of life.
The reports said at least two of the buried workers were Tibetan, while most of the workers were believed to be ethnic Han Chinese, a reflection of how such large projects often create an influx of the majority ethnic group into the region.
More than 1,000 police, firefighters, soldiers and medics have been deployed to the site. They conducted searches armed with devices to detect signs of life and were accompanied by sniffer dogs, reports said. About 30 excavators were also digging at the scene last night as temperatures plunged below freezing.