Some 107 people from 38 families were buried or trapped under a rain-triggered landslide in Southwest China's Guizhou province on Monday, local authorities said.
There were no signs of life at the scene, State broadcaster CCTV reported.
Xinhua News Agency said they had a "slim" chance of survival.
The landslide occurred at 2:30 pm in Dazhai village, Guanling county, said a spokesman for the government of Anshun city, which administers Guanling.
"Many villagers have been evacuated from the affected site," Wu Baocheng, a local press official, told China Daily.
Premier Wen Jiabao urged all-out efforts to rescue the victims. Vice Premier Hui Liangyu on Monday rushed to the site with a team of experts and officials.
Rescuers had to run five kilometers to reach the site, which is inaccessible by vehicles.
They used life-detecting devices to search for survivors after arriving at the scene, Xu Zhong, a senior local rescue official, told CCTV.
But they failed to find any signs of survivors as the sliding hillside had blanketed all the residences of the missing villagers, the report said.
Cen Chaoyang, a local villager, was feeding pigs when he heard rocks and mud sliding down the hill.
Cen rushed out of his home immediately and alarmed other villagers, he said over the phone, adding he had not seen any of his fellow villagers.
The village and areas nearby had been soaked by up to 200 millimeters of precipitation since Sunday evening, according to preliminary estimates.
It continued raining hard on Monday evening at the scene of the disaster, prompting the hill to continue sliding, Xinhua, quoted Wang Mengzhou, Guanling county's Party secretary, as saying.
Heavy rains made the rescue efforts more difficult, forcing rescuers to pull out of the site over fears of more major landslides, said Xu Zhong.
The local weather authority forecast no more heavy rains in the next two days.
Heavy rains and floods in South China had left at least 235 dead and 109 missing as of last Friday, said the Ministry of Civil Affairs in a statement.
A total of 3.05 million residents have been evacuated over the past two weeks.