As of late afternoon Thursday, 19,509 deaths in Sichuan province in southwestern China had been confirmed with tens of thousands more injured or missing, the official Xinhua news agency reported. Chinese Health Minister Gao Qiang said 12,587 of the 64,040 people hospitalized were severely injured and said efforts are in place to prevent epidemics from developing in the quake-ravaged area.

The 7.9-magnitude quake devastated a wide area, collapsing buildings -- 80 percent in one town -- and creating cracks in dams that threaten to fail and flood the areas around them.

More than 130,000 troops are aiding in rescue efforts, with 6,800 paratroops dropped into Devang and Mianzhu in Wenchuan County, which was virtually cut off due to road damage. Sniffer dogs also are being used in the search for survivors buried in the rubble.

China's Ministry of Education Thursday authorized schools to suspend classes. Many of the buildings were severely damaged by the temblor.

Xinhua reported that at least 270 students from a middle school in Qingchuan County were killed in the quake. Some 400 students were taking afternoon naps in the school when it collapsed. Eighty-four students have been saved from the rubble while 139 others escaped.

In Beijing, Foreign Minister Qin Gang said the country is deeply grateful for the support and aid coming from other countries. He said there is an urgent need for tents, blankets, food, medicine and communications equipment.