China's earthquake zone has been warned to prepare for heavy rains which could hamper further relief efforts.
There are concerns that construction of temporary shelters for five million homeless could be delayed, while water levels in dams and lakes remain high.
A 5.8 magnitude aftershock hit the area on Sunday, and was felt in Beijing, though there were no reports of damage.
State TV said one person was killed, several hundred were injured, and 70,000 homes were destroyed.
It was one of the strongest of about 8,000 aftershocks detected since the 7.9 quake on 12 May.
QUAKE STATISTICS
Up to Sunday 20 May:
62,664 people dead
358,816 injured
23,775 still missing
More than 5.4 million homeless
638,305 rescued and resettled
More than 8,000 aftershocks, biggest 6.0
69 dams faced danger of collapse, 310 in dangerous state and another 1,424 facing moderate risks
More than 300 more were affected by the earthquake, it added, saying many had been drained or had their water levels reduced.
There have been no reports of any dams breaking.
Thirty-four lakes were created in the province when landslides blocked rivers, Xinhua news agency said.
Eight held more than three million cubic metres of water and a lake at Tangjiashan, less than 3km (two miles) from Beichuan town, had doubled in size in four days.
Troops carrying explosives are heading for the lake to dig a sluice channel to allow a controlled release of water and prevent it from bursting.
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