A "slightly bruised" man was pulled out alive from a collapsed hospital Sunday after being trapped for 139 hours by China's massive earthquake, a state news agency reported. The official Xinhua News Agency said Tang Xiong was pulled to safety from the collapsed hospital in Beichuan in the northern part of Sichuan province. It said Tang "was only slightly bruised and in his right senses" when he was found. Experts say that buried earthquake survivors can last a week or more, depending on factors including the temperature and whether they have water to drink, but that the chances of survival diminish rapidly after the first 24 hours. The government says it expects the final death toll from last Monday's magnitude 7.9 quake will surpass 50,000. Xinhua said a second man was rescued from a different building in Beichuan about eight hours before Tang. It said the survivor, Wu Jianping, had been taken to hospital. His condition was not known. Xinhua also reported Sunday that flood threats from blocked rivers appeared to have eased after three backed-up rivers overflowed with no problems. It said county officials decided to let the rivers, blocked by landslides caused by the tremor, overflow and diverted water as a safety precaution. Xinhua did not give details. It quoted Liu Ning, engineer-in-chief with the Ministry of Water Resources, as saying some water facility projects, such as reservoirs and hydroelectric stations, had been damaged but that no reservoirs had burst. "The river levels have dropped," said a government official at the disaster command post in nearby Qingchuan. He refused to give his name. Xinhua said nearly 60,000 people live in seven towns and a county seat in the lower reaches of the three blocked-up rivers. Worries about possible flooding had sent thousands of people fleeing in the area still staggering from the country's worst disaster in 30 years. Frightened residents had streamed out of the entire county on the northern edge of the quake zone, spurred by mobile phone text messages sent en masse by local government officials warning that water levels were rising and people downstream were being evacuated. The swift exodus underscored the jitters that persist. A strong aftershock - the second in two days and measured by the US Geological Survey at magnitude 5.7 - shook the area early Sunday for 45 seconds, causing people to run into the streets. Cabinet spokesman Guo Weimin said 28,881 deaths have been confirmed so far as the death toll continued climbing toward an expected final tally of at least 50,000. Xinhua, citing regional officials, said more than 10,600 people were known to be still buried nearly a week after the earthquake shattered tens of thousands of buildings in dozens of towns and cities in Sichuan. Chinese President Hu Jintao has urged rescue teams to reach remote villages battered by the earthquake, according to Xinhua. He said the situation in many of them remained unclear. That was reinforced by a group of about 15 people who surrounded an Associated Press reporter at a gasoline station in Miangyang city Sunday, appealing for help for their village, Xiushui. "The government is doing nothing to help us," said one man who identified himself only by his surname, Chen. "If I gave you my complete name the government would track me down." He said Xiushui was about 20 kilometers from Mianyang, which is north of Chengdu. Chen did not say how many people lived there, handing over a note which said it had been signed "by the people of Xiushui." "Please go to our village of Xiushui to cover the situation. The government is doing nothing to help us get water or housing," the note said. More than 200 rescuers from Japan, Russia, South Korea and Singapore have been searching alongside Chinese soldiers. Xinhua said Russian rescuers found a 61-year-old woman alive late Saturday after she was buried for 127 hours - the first survivor discovered by foreign rescuers. "I express heartfelt thanks to the foreign governments and international friends that have contributed to our quake relief work," Hu was quoted as saying by Xinhua Sunday. More international aid was arriving, with a US Air Force cargo plane loaded with tents, lanterns and 15,000 meals landing Sunday in the Sichuan provincial capital of Chengdu. The number of security forces helping victims rose to almost 150,000, and the government added cash payments of US$715 to each family that lost a member.