Feng Jun carries a portrait of her dead son through the rubble of a collapsed school in Juyuan, in Sichuan. The boy was one of many students killed when the May 12 earthquake toppled the building.Feng Jun carries a portrait of her dead son through the rubble of a collapsed school in Juyuan, in Sichuan. The boy was one of many students killed when the May 12 earthquake toppled the building. (Eugene Hoshiko/Associated Press)

The official death toll in the Chinese earthquake passed 65,000 on Monday, as soldiers and police frantically worked to free a debris-clogged lake that was threatening to spark a major flood.

The 1,800 rescuers, carrying 10 kilograms of dynamite each, are staging an explosion designed to blast the rocks and rubble out of what is now being called Tangjiashan lake — a giant body of water that has pooled in the clogged Jianhe River, the Xinhua state news agency reported.

A helicopter on Monday carries an excavator to a 'quake lake' in Beichuan county, where 1,800 soldiers and police officers are working to dislodge the debris that is threatening to spark a flood.A helicopter on Monday carries an excavator to a 'quake lake' in Beichuan county, where 1,800 soldiers and police officers are working to dislodge the debris that is threatening to spark a flood. (Zhu Wei/Xinhua/Associated Press)

The soldiers and police spent a day trekking over hills and rubble to access the lake, which contains about 28 million cubic metres of water and is located 3.2 kilometres upstream from the main town in Beichaun county, Xinhua said.

Thousands of people still living in the area have fled due to flooding fears.

The lake is one of about 35 "quake lakes" that have formed after the 7.9 magnitude earthquake struck on May 12 in the central Sichaun province, triggering landslides that sent debris piling into lakes and rivers.

An estimated 14 million homes collapsed during the quake, leaving millions in desperate need of shelter, food and clean water.

On Monday, government spokesman Guo Weimin said the death toll has jumped to 65,080, up about 2,500 from the day before.

Premier Wen Jiabao has already said he expects the death toll to eventually surpass 80,000 from the May 12 earthquake.

Aftershocks have made the recovery efforts more difficult, including one with a magnitude of 6.0 that hit Sunday. It levelled an additional 71,000 homes and left 200,000 more in danger of collapse, Xinhua said.

With files from the Associated Press