At least four people have died and 49 more are missing after a mine collapsed in China's northern Inner Mongolia region on Wednesday.
Chinese leader Xi Jinping ordered a search and rescue operation which has so far found six survivors in the open-pit mine at Alxa League.
But desperate efforts to retrieve others were disrupted by a landslide on Wednesday evening.
More than 900 rescue workers have been deployed, Xinhua news agency reported.
President Xi has instructed authorities to make "every possible effort" to find survivors, state media reported.
Wei Zhiguo, leader of the rescue mission, said the rescue operation had been interrupted by a "large landslide" on Wednesday evening. This had halted some search efforts overnight.
"The rescue work is being carried out in an orderly and tense manner," he told state broadcaster CCTV.
The mine collapsed around 17:13 local time (09:13 GMT) on Wednesday affecting a "wide area" authorities said. It buried dozens of workers and vehicles.
CCTV reported the shaft had been operated by the Xinjing Coal Mining Company.
Mines in China's Inner Mongolia region are some of China's top coal producers.
Accidents are not uncommon in China, where industrial safety regulations can be poorly enforced. In December 2020, 23 miners died after a carbon monoxide leak at a coal mine.
And in January 2021, 10 miners were killed in a blast at a gold mine in Shandong province.
