Earlier plans to use explosives to breach a dangerous quake lake in the mountainous area of Tangjiashan have been abandoned, said state television.

'The lake problem is under control, we do not have any fears that there will be an uncontrollable flood,' said Mr Han Guijun, a top official in quake-devastated Beichuan county.

Hundreds of Chinese troops have been working round the clock for days to drain the Tangjiashan lake, which was formed when landslides triggered by the May12 earthquake dammed the Jian River in Beichuan.

Their work on a water-diversion channel to drain the lake is now complete, said the official Xinhua news agency, adding that around 350 soldiers, together with digging equipment, had yesterday been flown out of the lake zone.

Mr Yue Xi, deputy chief of the water and electricity section of the People's Armed Police Force, told Xinhua that the sluice was expected to drain water between today and Tuesday.

More than 5.2million people live in and around Mianyang, the nearest city to the Tangjiashan lake - the biggest of more than 30 quake lakes created after landslides blocked rivers.

Water levels in the lake have been rising steadily and it is now holding back enough water to fill 50,000 Olympic-sized swimming pools.

Nearly 200,000 people living downriver have been evacuated.

Xinhua reported that contingency plans provide for the evacuation of up to 1.3million people, depending on how the discharge of water from the quake lake proceeds.

Residents of Youxian on the outskirts of Mianyang have been ordered to move to higher ground in the hills around the town.

'We don't know how long they will have to stay up there. It depends on the situation with the dam,' a local police official, who declined to be named, told Reuters.

Long convoys of trucks yesterday drove into the disaster area piled with tents and other supplies for the evacuees.

An Airbus380 superjumbo, the world's largest passenger plane, flew into the regional city of Chengdu yesterday filled with emergency supplies.

'It's going to be a critical few days,' said Mr Francis Markus, spokesman for the International Federation of the Red Cross and Red Crescent societies, in a telephone interview from quake-stricken Sichuan.

'If more large evacuations are required, this will further strain what's already a very difficult humanitarian situation.'

A further 33 lakes were created by the May12 earthquake in mountainous Sichuan province, 28 of which are said to be at risk of bursting.

Yesterday, Chinese President Hu Jintao arrived to check on the relief efforts in Shaanxi province.

Just to the north of Sichuan, Shaanxi also suffered damage in the May12 quake, which has killed more than 68,000 people and left close to 18,000 missing.

AFP, AP, Bloomberg, Reuters