The death toll in the massive mudslides in northwest China's Gansu Province has risen to 1,117, with 627 still missing, local authorities said Wednesday.

A total of 567 survivors had received clinical treatment and further 64 seriously injured had been hospitalized as of 5:20 p.m., the provincial civil affairs bureau said in a statement.

The death toll stood at 702 Tuesday, with 1,042 others missing.

Hopes of finding any survivors faded as the thunderstorms battered the county seat of Zhouqu Wednesday night, nearly four days after the mudslides hit the town.

Heavy rains which are forecast through Friday could cause the artificial lake in Bailong River formed by being blocked by debris to burst and flood the already-devastated areas and put both survivors and rescuers at risk.

The provincial government has ordered a mass evacuation of residents in areas prone to flooding and geological disasters.

Zhouqu County sits in the steep valley of the Bailong River, a tributary of Jialing River, which meets the Yangtze in Chongqing, and is hemmed in by rocky mountains on both sides.

Torrential rain on Saturday night prompted an avalanche of sludge and debris to crash down on the county seat of Zhouqu early Sunday morning, ripping many houses off their foundations and tearing multi-story apartment buildings in half.

About 45,000 residents have been evacuated, as mudslides have destroyed more than 300 homes and damaged another 700. Moreover, 3,000 homes have been flooded.

Relief supplies are adequate for relocated residents in Zhouqu, Zhang Weixing, deputy director of the Civil Affairs Ministry's disaster relief bureau, told reporters Wednesday in Beijing.

Zhang said 7,038 tents, 20,000 quilts, 2,000 cotton coats, 5,000 sleeping bags, 8,000 folding beds, 49,000 packages of instant food, 56,000 packages of mineral water, 230 electricity generators, and 5,000 kilos of flour, had arrived in Zhouqu as of Wednesday noon, while more are en the route.

Relief materials could then reach Zhouqu earlier than expected as major roads into the remote town were reopened Wednesday after rescuers cleared the mud and rocks.

Business was gradually back to normal after 33 shops reopened Wednesday.

Relief teams were also sending tonnes of disease-prevention materials to the disaster zone.

Priority has also been given to infectious disease prevention in the summer raining season. Health authorities have disinfected an area of more than 171,000 square meters.

There have been no reports of an epidemic outbreak or public health incident in Zhouqu, Zhang Guoxin, vice director of the emergency office of the Health Ministry, told a press briefing Wednesday in Beijing.

Emergency medical rescue work was coming to an end and now epidemic prevention was the priority for health authorities, he said.

China suffers the worst flood in at least a decade this summer. Prior to the deadly mudslide in Zhouqu, floods had left 1,072 people dead and 619 missing this year nationwide, Shu Qingpeng, deputy director of the Office of State Flood Control and Drought Relief Headquarters, said on Aug. 4. Direct economic losses were estimated at 210 billion yuan (31 billion U.S. dollars).

In Tongxin County, Gansu's neighboring Ningxia Hui Autonomous Region, flash floods early Wednesday morning toppled 280 homes and forced the evacuation of more than 1,000 people.