Earthquake rescue workers in southwestern China are facing a new hazard after "extremely dangerous" damage was identified at a dam in Sichuan province as thousands of people remained buried in towns and villages downstream.
Two thousand soldiers have been sent to plug the cracks in the dam and have been told to avoid certain areas due to the risk of the dam being breached.
Recovery efforts following Monday's magnitude 7.9 quake have already been hampered by heavy rains.
Thousands of people are thought to still be buried under the rubble of collapsed buildings.
Wang Zhen Yao of China's ministry of civil affairs told Al Jazeera that communications with dozens of communities close to the epicentre of the quake had been cut.
As a result, he said, the toll could rise significantly once the full impact of the earthquake becomes clear. State media put the toll at just under 15,000 on Wednesday.
Al Jazeera's Melissa Chan, who visited a town in the area below the dam, said soldiers from China's People's Liberation Army who are leading recovery efforts have been asked to stay away from certain areas because of the danger posed by the damaged dam.
Chinese officials say nearly 400 dams have been damaged.
In the city of Mianyang alone, close to the epicentre of the quake, more than 18,000 are believed to have been buried in the rubble of collapsed buildings.
About 100,000 troops and police have been deployed to the region, but several of the hardest-hit areas remain largely inaccessible because roads have been cut by landslides.
Chinese air force has also been brought in to drop emergency food and relief supplies to survivors.
|Tens of thousands are still buried under rubble|
across the affected region [GALLO/GETTY]
In the town of Dujiangyan, power and water supplies remain cut while the local hospital was unable to help the injured because it had its own cave-in to deal with.
Ongoing aftershocks have triggered panic and raised fears of further building collapses.
In Sichuan's provincial capital of Chengdu, 24-hour radio station FM 91.4 was reading out text messages sent by survivors in stricken areas to let relatives know they were safe.
More rain is forecast in the region over the next few days and landslides could further hinder relief work.
Only 58 people have been pulled from destroyed buildings across the quake area so far, Zhang Hongwei, a spokesman for China's Seismological Bureau, told state-run Xinhua news agency.
Wen Jiabao, China's premier who toured the disaster area to oversee relief efforts on Tuesday, called for air drops of emergency supplies to hard-to-reach areas, but rain had impeded those efforts.
In the hard-hit city of Mianyang, the government has ordered residents to stay away from damaged buildings fearing further aftershocks, and security guards were posted at apartment blocks to keep people out.
The industrial city of 700,000 people is home to the headquarters of China's nuclear weapons design industry, and the quake has sparked fears of a potential leak of radioactive material.
Aid agencies such as the International Red Cross and Oxfam are pouring money and supplies into the region.
| Damage to local hospitals has put a further |
stretch on recovery efforts [EPA]
Russia said it was sending an aircraft with 30 tonnes of relief supplies while the US is offering an initial $500,000 in aid.
The government said it welcomed outside aid, but officials said that the assistance would be confined to money and supplies, not to foreign personnel.
"We welcome funds and supplies. We can't accommodate personnel at this point," Wang Zhenyao, the Civil Affairs Ministry's top disaster relief official, told reporters in Beijing.
Bowing to public calls, Olympics organisers scaled down the ongoing national torch relay, saying Wednesday's leg in the southeastern city of Ruijin will begin with a minute of silence and more sombre ceremonies.
People along the relay route - which next month is scheduled to travel through quake-hit areas - would be asked for donations, an organising committee spokesman said.