Desperate for shelter, their lives in shards around them, it was the moment that five million refugees in Sichuan province have dreaded for two weeks – a massive aftershock and another terrifying wave of destruction.

With ominous rainclouds gathering overhead, and with the Government betraying its rising panic over the possible collapse of the “quake lakes”, the stricken province was hit by a tremor that measured 6.4 on the Richter scale.

The aftershock came moments after the Chinese Government had revealed its deepening concern over the security of nearly 70 dams throughout the worst-hit region, which it said were at high risk of bursting. Another 310, said the authorities, were in “highly dangerous” states.

With two days of heavy rain forecast, a squad of 1,800 soldiers, each bearing a 10kg sack of explosives, were sent up into the mountains on a mission to save thousands of lives.

With the waters in the Tangjiashan lake more than 2 metres higher than on Friday, the soldiers hope to blast a hole in the barrier of debris so that water flows down the river gradually. If their efforts fail, and the dam bursts under mounting pressure, floods would devastate what little remains in the valley.

For the refugees scattered around the area, though, the aftershock presented a more immediate threat.

Villagers have watched with rising fear as rocks and great slabs of earth have tumbled down the mountains in recent days.

“At nighttime you can hear the rumbling from the landslides around here and sometimes the earth shakes,” said Yang Daifu, 70, a farmer from Nongwan village.

The tremor, which was centred 155 miles northeast of the provincial capital and was felt in Beijing, is thought to have reduced another 70,000 homes and other buildings to rubble.

Hundreds are feared to have been injured by the violent tremor and several people joined the rising death toll from the original quake.

Over the weekend, the Chinese government raised the official toll since May 12 to 62,664.

However, there was one small glimmer of hope.On Friday, an 80-year-old man was rescued alive from the rubble of his home.

He had lain for 266 hours in the ruins of his house, while his wife passed food and water to him through cracks in the rubble.

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