BEIJING (AFP) - The death toll from a powerful earthquake in China has exceeded 12,000 in Sichuan province alone, the official Xinhua news agency reported on Tuesday, quoting the local government. The number of dead from the 7.9-magnitude quake, which struck Sichuan on Monday, had reached more than 12,000 as of 4:00 pm (0800 GMT) on Tuesday, Xinhua said. Chinese soldiers and relief workers trudged through rugged terrain and driving rain on Tuesday in a frantic race to reach devastated communities cut off by a powerful earthquake. The United Nations is ready to send aid if China seeks help in dealing with the aftermath of the massive earthquake that rocked the country's southwest, a UN spokeswoman said Tuesday. Meanwhile, French nuclear experts on Tuesday said damage to nuclear facilities close to the epicentre of China's massive earthquake could not immediately be ruled out. The Institute for Radiological Protection and Nuclear Safety said it was unlikely that China's four nuclear power plants Daya Bay and Lingao in the south, Qinshan in the east and Tianwan in the northeast had been badly damaged. They are all more than 1,000 kilometres from the epicentre, which was in the southwestern province of Sichuan. China's massive army is spearheading the desperate relief effort following Monday's 7.9-magnitude earthquake in the country's southwest, with 54,000 People's Liberation Army troops in the disaster zone or on their way. A national blood drive also was launched to supply the tens of thousands of survivors, while the nation's private airlines were called in to transport aid, and the Red Cross Society of China appealed to all Chinese for cash donations. However, bad weather and the destruction of roads severely hampered the effort, forcing relief teams to hike into areas ravaged by the quake, which has killed nearly 12,000 people so far and reduced schools and factories to rubble. The PLA had planned to parachute troops and supplies into areas at the quake's epicentre, a mountainous county in Sichuan province called Wenchuan with a population of just over 100,000 people. But heavy rain and clouds scuttled those plans, the state-run Xinhua news agency said. "Helicopters are prepared to airlift food, medicine and water to the area once weather conditions allow," Li Shiming, a lieutenant general in the PLA, told state television. The air-drop order had been issued to "speed up deployment of rescuers" in Sichuan and neighbouring areas, Xinhua said, amid reports that tens of thousands of people were missing or stranded without clean water and in urgent need of medical care. Premier Wen Jiabao, who flew to Sichuan late Monday to oversee rescue efforts from Dujiangyan city about 50 kilometres from the epicentre, appeared to express impatience on Tuesday with the pace of relief efforts. "We must try our best to open up roads to the epicentre and rescue people trapped in the disaster-hit areas," he told an emergency meeting of aid workers, according to Xinhua. Other small teams were reported to be trickling into the worst-hit area north of the Sichuan provincial capital of Chengdu. State television broadcast images showing mountainsides had sheared off in landslides triggered by the quake, heavily damaging highways leading to affected communities. In other areas, the highways themselves had slid down hillsides or were riven by huge fissures. Meanwhile, residents of remote yet heavily populated areas desperately awaited help in digging out those trapped under their homes, schools and factories and in treating the injured. Zhu Jixiang, a Red Cross worker in Mianyang city about 110 kilometres from the epicentre, told AFP by phone that vital supplies were critically short in the worst-hit areas. Meanwhile, the Red Cross Society of China launched a nationwide appeal for cash donations to help buy badly needed tents, quilts, food and drinking water. The health ministry also launched a blood donation drive on Tuesday. The nation's state-controlled airlines also joined in, with Air China, China Southern Airlines and China Eastern mobilising to transport relief workers, Xinhua reported.