DUJIANGYAN, China - The toll of the dead and missing soared as rescue workers dug through flattened schools and homes on Tuesday in a desperate attempt to find survivors of China's worst earthquake in three decades.

The official Xinhua News Agency said the death toll exceeded 12,000 in Sichuan province alone, and 18,645 were still buried in debris in the city of Mianyang, near the epicenter of Monday's massive, 7.9-magnitude quake.

The Sichuan Daily newspaper reported on its Web site that more than 26,000 people were injured in Mianyang.

The numbers of casualties was expected to rise due to the remoteness of the areas affected by the quake and difficulty in finding buried victims.

There was little prospect that many survivors would be found under the rubble. Only 58 people were extricated from demolished buildings across the quake area so far, China Seismological Bureau spokesman Zhang Hongwei told Xinhua. In one county, 80 percent of the buildings were destroyed.

Rain was impeding efforts and a group of paratroopers called off a rescue mission to the epicenter due to heavy storms, Xinhua reported.

Panda-watching tourists missing
More than two dozen British and American tourists who were thought to be panda-watching in the area also remained missing.

Officials urged the public not to abandon hope