SICHUAN PROVINCE, China (CNN) -- China's death toll from a massive earthquake soared by thousands Wednesday as troops rushed to a dam feared critically damaged.
A heavily pregnant Zhang Xiaoyan is pulled alive from an apartment which collapsed in Dujiangyan.
About 2,000 troops were sent to work on the dam near the epicenter of Monday's earthquake, after reports of severe cracks, state-run media reported.
The Ministry of Water Resources warned that an irrigation system and Dujiangyan City -- which has a population of about 630,000 -- "would be swamped," if major problems emerged at the dam, China.org said.
Late Wednesday, Xinhua reported the Zipingpu Dam was stable and safe after investigation
The Zipingpu dam, upriver from Dujiangyan in Sichuan province, was in "great danger," the Xinhua news agency reported. Watch a report on efforts to fix the dam »
China.org said that the 7.9-magnitude earthquake had caused "severe cracks" in the dam. See where the dam is located »
The "plant and associated buildings have collapsed and some are partly sunk," it said of the hydropower station.
Xinhua earlier reported that the death toll had risen to 14,866. An unofficial tally of deaths in individual communities -- as reported by the news agency over several days -- puts the toll at 19,565.
Xinhua also said nearly 26,000 people were still buried under debris and another 14,000 missing. More than 64,000 people sustained injuries. Watch report on plight of survivors »
Rescuers announced a piece of good news Wednesday, hailing the rescue of an eight-months pregnant woman as a "miracle," AP reported.
Zhang Xiaoyan spent 50 hours trapped in debris after an apartment building collapsed in Dujiangyan. Watch Zhang Xiaoyan being rescued »
Meanwhile, Chinese Premier Wen Jiabao was touring some of the worst-hit areas, according to the Xinhua news agency.
He visited a stadium in the city of Mianyang, which has become a massive camp for survivors streaming from their destroyed homes.
Thousands of people uprooted around the region are taking shelter in downtown Mianyang's main sports gym and other facilities converted into rescue centers.
The government has transported homeless people from other areas to the city center because the sports gym is a safe and huge facility. Watch survivors find refuge in Mianyang »
Men, women and children -- numbed and overwhelmed by the sudden tragedy -- are huddled in the huge stadium as truckloads of aid and private donations, such as water, food and clothes, roll in.
Chinese companies, such as TV set-maker Changhong, located in Mianyang, are helping the refugees, Xinhua news agency reports. Some companies are ordering their staffers to cook for the homeless and have provided supplies, such as batteries and flashlights.
"Time is life," said Wen, who is heading up China's relief effort.
Local officials said the quake killed more than 7,700 people in the town of Yingxiu -- about three-quarters of the population, according to Xinhua. Watch children being pulled from the rubble »
Yingxiu is in Sichuan province, where 20,000 Chinese soldiers have been mobilized for rescue and recovery, state media reported. Another 30,000 were en route to the region -- many using rail lines that are also transporting supplies.
"The top priority for the railway network in China is to deliver disaster-relief troops, personnel and goods to the affected area as soon as possible," said Wang Yongping, spokesman for the Ministry of Railways. He said many passenger trains would be diverted to ferry troops.
Rubble hides quake's terrible toll
Wednesday brought new horrors from the rubble. Watch new footage of the quake
At one three-story school in Sichuan's Qingchuan county 178 students were confirmed dead after the building collapsed, a local official said.
Rescuers found at least 500 dead Tuesday in the Chinese district at the epicenter of the quake. Heavy rain, collapsed bridges and damaged roads complicated efforts to get troops and aid workers to the worst-hit towns. Watch rescuers dig for victims »
"We will do our utmost to reopen the links to epicenter as soon as possible -- so as to restore the transportation links to the whole province," said Feng Zhenglin, China's vice minister of transport.
The epicenter of Monday's quake was in Wenchuan county, Sichuan, about 1,500 km (960 miles) southwest of Beijing.
During a visit to a school in Shifang, where more than 100 children were trapped beneath rubble, Wen promised that saving lives was a top priority.
"We will put our best efforts forward to save all those alive who can be saved," he said. "This disaster has all tested us. We all have to band together and have confidence and push forward."
More than 30,000 people are "missing or out of reach" in Shifang, where local government officials told Xinhua the city's death toll exceeded 2,500.
An ammonia leak from a collapsed chemical plant in the city was plugged Wednesday, Xinhua reported.
All the beds were filled at Sichuan University Huaxi Hospital, one of the largest in the provincial capital of Chengdu.
Nurses said the most common injuries were broken bones, bruises and scrapes. State media reported thousands of victims had sought care at the hospital, where medical supplies were running low. View a photo wall of damage and rescue efforts »
Fear of becoming trapped during an aftershock led about 200 people to sleep outside in cots, on lawn chairs and on the ground outside the hospital in an area intended for bicycles.
At the Third Military Medical University Southwest Hospital, state-run media reported that nurses and doctors were donating their own blood.
Millions of homes destroyed
China is no stranger to natural disasters: A 1976 earthquake here killed more than 250,000 people. But analysts said the Chinese response to Monday's quake had been the most transparent of any disaster, with state media frequently updating casualty tolls and deploying troops rapidly to the worst-hit areas.
Li Chengyun, vice governor of Sichuan, said about 3.5 million homes were destroyed in the province. David Jones, an English teacher in the city of Chengdu, said: "People are doing everything they can to stay outside," he said. "In a lot of cases, they can't return to their buildings."
Wenchuan is the refuge for much of China's panda population, and the State Forestry Administration said the 67 captive pandas among the more than 130 pandas in the Wolong Giant Panda Reserve were not injured. However, the caregivers were worried about the bamboo leaf supply.
CNN correspondents John Vause, Paula Hancocks, Eunice Yoon and Judy Kwon contributed to this report.