Beijing - Almost two weeks after the earthquake in south- western China, the confirmed death toll rose Sunday to 62,664, the official Xinhua news agency cited the government as saying.

Almost 24,000 people were still missing, the report said, and Premier Wen Jiabao said he feared that the total number of dead could exceed 80,000.

Another aftershock, initially measured at 5.8 by US seismologists but later placed at 6.4 their Chinese counterparts, struck the region Sunday, causing panic.

Strong aftershocks and heavy rain have increased the risk of barrier lakes formed during the main quake of bursting their banks.

The situation was 'grim,' Vice Minister of Water Resources E Jingping was quoted by Xinhua as saying on Sunday in Beijing.

Forecasts for heavy rain in the next three days were 'a major threat' and could cause the lakes to burst releasing floodwaters, E was quoted as saying.

There are 35 natural lakes caused by landslides that blocked rivers during the earthquake.

The Chinese Army told Xinhua that some 1,600 soldiers were on the march to one of the largest lakes near Tangjiashan, three kilometres upstream from the county town of Beichuan.

They plan to use dynamite to blow up parts of the massive rock, rubble and earth wall formed in the area to release water.

An attempt to fly the troops in by helicopter failed owing to bad weather and poor visibility.

State television meanwhile reported that an 80-year-old man was rescued from a collapsed building after surviving for 11 days helped by his wife handing in water to him.

The report said the man had been bound to his bed because he was partially paralysed. He was not injured when the building collapsed and was found hiding under a support beam.

Rescue troops found the elderly couple on Friday in the city of Mianzhu in Sichuan province. Using their bare hands, the troops moved the beams and rubble to pull the man from the building.

Premier Wen Jiabao returned to Beijing Sunday following his second visit to the earthquake-hit region.

Wen said he estimated that the number of dead from the 8.0- magnitude quake could 'further climb to a level of 70,000 or 80,000 or more.'

Wen met UN Secretary General Ban Ki-moon on Saturday in the badly damaged city of Yingxiu near the epicentre of the earthquake. Ban was in the area to familiarize himself with the post-quake situation.

After visiting Sichuan, Ban flew on to Myanmar to chair a donor conference for victims of Cyclone Nargis.