BEIJING — More than 140 people in southwestern China are feared to have been buried under an avalanche of mud and rocks when a hillside collapsed on Saturday, Chinese news media reported.

The landslide struck Xinmo, a village in Sichuan Province, early in the morning. Although the number of possible deaths remained unclear, officials estimated that 40 homes appeared to have been engulfed, Sichuan Online, a provincial news agency, reported. At that hour, many residents would probably have been in their homes.

Xinhua, the official news agency, said that 141 people were missing. The Communist Party secretary of Sichuan, Wang Dongming, and other officials were rushing to the village, in a sign of the gravity of the disaster, Sichuan Daily said.

Li Yuanjun, a local official who arrived in the village shortly after the slide, said he saw near total devastation. “In the entire village I could only see one home,” Mr. Li told the Sichuan Daily. “The rest had been totally buried by rocks.”

The police and rescue workers arrived at the village and began searching buried ruins for survivors. There were reports that at least a few people had survived. State media outlets said a couple and their baby had been rescued. Still, many people appeared to be trapped in their homes.

Some residents stuck under the mud and rock used cellphones to call emergency lines, according to local news reports. One woman cried out from under the earth, Wang Yongbo, a firefighter, told Chinese television news.

“A woman shouted and dozens of troopers heard her and asked her questions,” Mr. Wang said. She “could only use a stone to tap in response,” he said.

Initial accounts from villagers and nearby residents said there had been rain in the area, but some said it was not very heavy and there were no signs of the impending landslide. The area was badly hit by an earthquake in 2008 that killed tens of thousands of people in Sichuan and nearby provinces.

“It came too suddenly,” the employee of a nearby hotel told The Paper, a Shanghai news site, of the landslide. “I didn’t sense any signs before it happened.”

Photographs from the scene indicated that a thinly vegetated side of a hill had toppled into a narrow valley, creating a wall of muddy earth and stones that covered a road and choked off a small river. Mao County, which includes Xinmo, announced a state of emergency and said rescuers were heading to the village.

By midmorning Saturday, about 500 rescuers and medical workers were converging on the area, one news report said. But officials said they were unsure how many people might have been buried by the landslide. China’s schools are on vacation, so there may have been more children in the village than usual, and the scenic area also attracts tourists.

One local police commander, Chen Tiebo, said there might have been as many as 200 people in the village, China Central Television said.

Western Sichuan Province, where the disaster hit, is a mountainous and remote part of the country, and the region has had landslides before. A landslide in the province in 2013 buried about 40 people; another in 2014 killed at least 11 people.

The earthquake in 2008 with an epicenter in Sichuan left nearly 90,000 people dead or missing and presumed dead after the tremors set off landslides and blocked rivers, which multiplied the risks from more slides. Investigators are likely to look at whether the quake left the slope above Xinmo Village vulnerable.

Rescuers said the latest slide had also created a potentially dangerous 1.2-mile-long blockage along the river near the buried village. Rain is forecast for the area in the coming days.