A woman evacuated from Qinglian town looks out from a hill refuge overlooking the town on Taohua hill in southwestern China's Sichuan province. Authorities are trying to drain the Tangjiashan quake lake formed after the earthquake. (Ng Han Guan/Associated Press)

U.S. President George W. Bush on Friday thanked China for "welcoming our aid" after a devastating earthquake struck last month and praised Beijing's strong response.

"No question, this is a major human disaster that requires a strong response from the Chinese government, which is what they're providing," Bush said on a visit to the American Red Cross headquarters in Washington. "But it also requires a compassionate response from nations that have got the blessings of life, and that's us."

Bush praised Americans for helping victims of the May 12 earthquake, calling the response "impressive" and "unprecedented."

"My message to the Chinese government is: thank you for welcoming our aid, thank you for taking a firm response to this disaster and just know the American people care about the people of China."

Chinese soldiers are continuing efforts to prevent further destruction as an earthquake-created lake threatens to spill over, endangering the homes of tens of thousands of people in the area.

State television reported Friday that soldiers have been ordered to deepen a diversion channel to speed the draining of the lake, which formed when a landslide set off by the earthquake blocked a river.

The 7.9-magnitude quake killed 69,127 people with 17,918 still missing, according to the latest government figures. About 15 million were also left homeless.

State media reported that more than 250,000 people living in low-lying downstream areas had been evacuated as of Thursday.

A 400-metre-long, 11-metre-deep spillway has been dug to release pressure on the wall of mud and rock holding in the Tangjiashan lake, but around 8 a.m. Friday, the water level was less than a metre beneath the spillway.

State news agency Xinhua also reported that by midday Thursday, domestic and foreign donations reached $6.33 billion. The government's National Audit Office has announced it will "investigate and deal with any attempt to hide, intercept or misappropriate" donated funds and materials following several complaints of aid misuse.

With files from the Associated Press