An overnight downpour has brought new disaster to northwest China's mudslide-ravaged town of Zhouqu, leaving three people missing, said local authorities Thursday.

The downpour triggered floods and mudslides along the Bailong River in Zhouqu County, Gansu Province.

Three people disappeared when six houses were swept away in Xizangba Village, according to a spokesman with the disaster relief headquarters.

He said one of the mudslides in Libazi Village formed a blockage on the river, raising the water level by three meters early Thursday.

Another mudslide blocked a major "lifeline" road along which relief goods were carried into the town. An estimated 45,000 cubic meters of debris covered the Lianghekou-Zhouqu Road, the shortest route for bringing goods from the provincial capital of Gansu to Zhouqu.

The headquarters had sent workers aided with heavy machinery overnight to repair the road, said the spokesman.

A surge of fresh floodwater in the Bailong River had passed through the barrier lake in Zhouqu without causing havoc, Liu Ning, vice minister water resources, told Xinhua Thursday.

The provincial weather station said 15 to 30 millimeters of rain fell on Zhouqu from 9 p.m. Wednesday to 8 a.m. Thursday.

Heavier downpours forecast for the next 24 hours were expected to bring 40 to 60 mm of rain, and in some areas, up to 90 mm, it said.

Heavy rains have been forecast through Friday, posing dangers to survivors and rescuers.

Dozens of rescuers were called out at midnight after searching for hours in vain for survivors, said Zhang Guiquan, an army officer Thursday morning.

Zhang said they were told by locals that cries had been heard from a partially collapsed building near the swollen Bailong River. About 40 soldiers braved heavy rains and potential mudslides to search the site.

"We will seize every chance to finding survivors, but it is also important to ensure the safety of rescuers," he said.

Luo Binghong, like many other mudslide victims, had a sleepless night at a temporary shelter.

"I sat all night listening to the sound of rain," she said, huddled with three relatives on a wet bed.

At temporary shelters in two middle schools, rain water had seeped in, soaking straw mats and carpets. Many victims chose to stay in the building corridors at night.

Work teams dispatched by the Ministry of Land and Resources announced Thursday that there were 18 potential geological danger sites in the county and nearby regions, affecting nearly 30,000 people.

The county's water plant used to provide 6,000 tonnes of water every day, but the disaster had damaged many water sources and also paralyzed the county's water supply network, said Zhou Yingjun, deputy head of the provincial construction department.

"We are racing to repair the permanent water supply network," Zhou said at a news conference held 5 p.m. Thursday.

From Wednesday morning, emergency water supply vehicles began providing safe drinking water to the county. The daily output of which was 300 tonnes, enough to sustain some 30,000 residents and rescuers in the county, Zhou said.

The Ministry of Civil Affairs had dispatched another two emergency water supply vehicles to the county, which could provide drinking water to 2,000 people every day, he said.

Some medical experts were trying to identify 52 unclaimed bodies after extracting DNA samples from them, said Li Zongfeng, deputy head of the provincial public security department.

The death toll from the massive mudslides in the early hours of Sunday had risen to 1,117, with 627 still missing as of Wednesday.

A total of 567 survivors had received clinical treatment and 64 seriously injured had been hospitalized, the provincial civil affairs bureau said in a statement.