BEIJING » Rescue workers cleared roads Saturday so they could search for survivors and rush aid to a remote mountainous area of southwestern China after twin earthquakes killed at least 80 people.

More than 200,000 villagers were evacuated after Friday’s quakes toppled thousands of homes and sent boulders cascading across roads in a region of small farms and mines near the border between Guizhou and Yunnan provinces, where some of China’s poorest people live.

The official Xinhua News Agency quoted local officials as saying the death toll could climb further because the quakes seriously damaged roads and communications, making it difficult to collect information.

The damage also slowed rescue efforts.

“Roads are blocked and rescuers have to climb mountains to reach hard-hit villages,” Xinhua quoted Li Fuchun, head of Luozehe township in hardest-hit Yiliang County, as saying.

State television said Saturday that workers had succeeded in clearing a road into the worst-hit area that had been blocked by fallen boulders, allowing rescuers and assistance in.

Rescue work was also likely to be hampered by rain forecast over the next three days. There was, however, some uplifting news: State television reported that four babies had been born in temporary hospitals set up after the quakes.

The first magnitude-5.6 quake struck just before 11:30 a.m. Friday and was followed by an equally strong quake shortly after noon, joined by dozens of aftershocks. Though of moderate strength, the quakes were shallow, which often causes more damage than deeper ones.

Zhang Junwei, a spokesman for the Yunnan Seismological Bureau, said by telephone Saturday that 80 people had died and 821 others had been injured.

All but one of the deaths occurred in Yiliang County, according to the Yunnan provincial government’s official website. Yiliang’s high population density — twice the provincial average — along with flimsy building construction and landslide-prone hillsides were blamed for the relatively high death toll.

The dead included three primary school students, Xinhua said. It cited Zhou Guangfu, deputy chief of the Yiliang county education bureau, as saying 15 students were in their classroom in Jiaokui township when the first quake hit. Eight were buried in rubble and teachers and villagers were able to rescue five of them, he said.

CCTV footage showed heavy equipment being used to clear roads littered with rocks and boulders.

Other footage showed tent villages full of survivors, and search dogs going through the rubble of destroyed homes. Several vehicles were crushed by large boulders that had swept down mountainsides.

Chinese Premier Wen Jiabao visited the quake area on Saturday and was shown on television consoling survivors and walking through hospitals.

Wen warned of aftershocks and the “need to guard against secondary and geological hazards,” apparently referring to the possibility of landslides. Many of the roads in the area are at the bottom of valleys.

Though quakes occur in the area frequently, buildings in rural areas and in fast-growing smaller cities and towns are often constructed poorly. A magnitude-7.9 quake that hit Sichuan province, just north of Yunnan, killed nearly 90,000 people in 2008, with many of the deaths blamed on poorly built structures, including schools.

Yunnan’s civil affairs department said Friday’s quakes destroyed 6,650 houses and damaged 430,000 others. It said direct economic losses in Yunnan so far are estimated at $551 million.

Yunnan Gov. Li Jiheng said that as long as there was “a ray of hope” of finding anyone alive, all efforts would be made.

Xinhua said more than 21,000 tents, 31,000 quilts and 26,000 winter coats had been sent to Yunnan. The government said thousands of soldiers were helping the rescue effort in the area, which is largely inhabited by members of the Yi ethnic minority.

Mobile phone service was down and regular phone lines disrupted. Phones were cut off to clinics in four villages in Qiaoshan, another town in Yiliang, which has about half a million people.

Xinhua said that so far no deaths had been reported in neighboring Guizhou, but that homes had been damaged or destroyed there.

Friday’s quakes were relatively shallow, about 10 kilometers (six miles) deep, creating an intense shaking despite their moderate magnitude.

By comparison, the magnitude-7.6 quake in Costa Rica this past week was 25 miles below the surface, which, combined with strict building codes, kept damage and deaths to a minimum.