BEICHUAN, China — China said the toll of dead and missing from last week's powerful earthquake jumped to more than 80,000, while the government appealed today for millions of tents to shelter homeless survivors.

The confirmed number of dead rose nearly 10,000 from the day before to 51,151, Cabinet spokesman Guo Weimin told a news conference. Another 29,328 people remained missing and nearly 300,000 were hurt in the May 12 quake centered in Sichuan province, he said.

The disaster left 5 million people homeless and leveled more than 80 percent of the buildings in some remote towns and villages areas near the epicenter. In bigger cities whole apartment blocks collapsed or are now too dangerous to live in because of damage and worries about aftershocks.

"We need more than 3.3 million tents," Foreign Ministry spokesman Qin Gang told reporters, adding that 400,000 tents have already been delivered. It was the second call for tents from China in recent days.

Underscoring the need, Chinese President Hu Jintao visited two tent manufacturing companies in eastern Zhejiang province, urging workers to boost production to meet needs from the disaster area, state media reported.

U.S. aid to earthquake victims totals $2.8 million, Ambassador Clark T. Randt Jr. said, including medical equipment and satellite images of damaged infrastructure. The American Red Cross had donated $10 million, and American companies in China have pledged more than $34 million.

In the effort to assure people the government was placing top priority on relief efforts, Premier Wen Jiabao returned today to the disaster zone, the official Xinhua News Agency said — his second trip there following a visit immediately after the quake.