Beijing  - Chinese engineers Saturday began to release water out of Tangjiashan lake formed by a huge landslide during the Sichuan earthquake.

Officials feared that a massive torrent of water could be released if the earth that formed the body of water ultimately fails to hold the lake back.

Tangjiashan is the biggest of as many as 35 lakes that were formed in the valleys of eastern Sichuan province when mountainsides collapsed during the May 12 quake.

Engineers hope that a channel built to drain the lake will prevent it from flooding parts of Mianyang, a city of 5 million people about 50 kilometres away.

Some 250,000 people have been ordered out of areas downstream of the lake and efforts are being made to evacuate as many as 1.3 million.

The lake contains more than 220 million cubic metres of water and authorities are worried that aftershocks or rain could trigger more landslides, which could lead to catastrophic flooding.

Two millimeters (0.08 inches) of rain may raise the water level by 1 metre, Liu Ning, the chief engineer of the Ministry of Water Resources, said last week.

Rain is forecast Saturday, said the China Meteorological Administration on its Web site Friday.

The death toll from the quake rose to 69,130 people with 17,824 missing, the State Council Information Office said Friday.

The May 12 earthquake was the most powerful to hit China since a magnitude 8.6 quake struck Tibet in 1950, killing 1,526 people. A 7.5 magnitude quake in Tangshan in northeast China killed 250,000 people in 1976, according to the U. S. Geological Survey. China's seismology department said the Sichuan quake registered 8 on the Richter Scale. (dpa)