The death toll from Monday's earthquake could climb as high as 50,000, China's state council said on Thursday as rescue workers continued to struggle to reach some of the worst affected areas. The number of deaths announced so far has reached 19,500 in Sichuan province, where the earthquake was centred. However, the sharp escalation in the expected death toll indicates that hopes are fading for the tens of thousands of people who are still buried under collapsed buildings. Meanwhile, there were new concerns about the safety of the many dams in the region after Huaneng Power, one of the country's largest power producers, said that two dams upstream of its hydropower station in Sichuan could collapse "at any time". The government warned on Wednesday that as many as 391 dams had been damaged by the earthquake, which measured 7.9 on the Richter scale. In spite of a massive relief effort involving 100,000 soldiers and police, there are still several areas near the earthquake epicentre that can only be reached by air and the authorities are planning to deploy more than a 100 further helicopters to the region. As the scale of the disaster continues to grow, the government issued a rare public appeal for assistance, asking for donations of rescue equipment including cranes, concrete-cutting tools, body-heat detectors and rubber boats. 50,000 more shovels were also required. The authorities have also begun to ask for assistance from overseas disaster experts to help the relief effort, having so far only accepted offers of money or supplies on the grounds that it was logistically difficult for foreigners to work in the disaster area. Japan said it would send two groups of 30 rescue workers on Thursday night to China, who are expected to bring sniffer dogs and heat-sensing equipment. Osamu Sakashita, deputy cabinet secretary, said Japan's rescue workers would be dependent on Chinese help to move around the area and were anxious to ensure they were a help and not a burden to the relief effort. Taiwan's Red Cross is sending a team of disaster relief specialists while the Taiwanese government is also sending a planeload of supplies to Sichuan, including tents and medicines.