Beijing - A strong aftershock, rain and minor floods battered earthquake-devastated areas of south-western China on Sunday, as the confirmed death rose to about 32,500 and rescuers continued to find more survivors buried in collapsed buildings.

An aftershock measuring 6.0 on the Richter scale shook areas near Jiangyou city in Sichuan province at 1:08 a.m. on Sunday (1708 GMT Saturday), the government said.

The tremor was the latest of more than 20 aftershocks of 5.0 or higher in Sichuan since a 7.9-magnitude earthquake on Monday.

The government said the casualty toll in Sichuan and neighbouring areas had risen to 32,477 dead and 220,109 injured by Sunday afternoon.

Three natural lakes, formed after landslides blocked a river, overflowed early Sunday in Sichuan's Qingchuan county but caused no immediate danger to some 600,000 residents of towns and villages downstream, the official Xinhua news agency said.

More than 10 million cubic metres of water were estimated to have accumulated in the three lakes, the agency quoted earthquake relief officials as saying.

Water burst from another barrier lake on Friday along the Jianjiang river near Sichuan's Pengzhou city, but residents downstream were evacuated in time and no casualties were reported, the agency said.

On Saturday, residents of nearby Beichuan began rushing onto hillsides after reports that a barrier lake formed upstream was imminent danger of flooding the town.

The river through the town had almost dried up, witnesses said, because a landslide had blocked it and formed the lake.

Xinhua earlier Saturday said the military had ordered the evacuation of injured people from the town, where only 10,000 of the 30,000 residents were reported to have survived Monday's devastating quake.

The earthquake destroyed hundreds of thousands of buildings, killed at least 30,000 people and left some five million homeless.

Rescuers found another survivor in Beichuan on Sunday, 139 hours after he was buried in a collapsed building.

The man, whose wife was also rescued on Thursday, was coherent and had only minor injuries, reports said.

At least 63 people were rescued on Saturday in Sichuan, where thousands of others were believed to be still buried under rubble, the agency said.

Rescue and relief efforts were hampered by rain in Qingchuan and other areas on Saturday, bringing more hardship to some of the many homeless people who were sleeping outdoors or in makeshift tents.

Experts feared continued rainfall could raise the risk of flood from the river above Qingchuan.

In Gansu province, which borders Sichuan, mud and rock swept away two cars but caused no casualties after a 40-minute storm battered Chengguan town on Saturday, the agency said.