China quake lake now 'critical'

A massive emergency effort has swung into action to ease the quake lake

Chinese Prime Minister Wen Jiabao said efforts to ease a swollen quake lake had reached a "critical moment", as he flew to oversee the relief work.

He boarded a helicopter to see the lake at Tangjiashan after going to Sichuan province, Xinhua state media said.

The authorities have warned that the lake, formed by a landslide after the 12 May quake, has become more unstable.

A magnitude 5.3 aftershock hit Sichuan as workers prepared to drain the lake through a long specially-dug channel.

There were no immediate reports of new damage or injuries from Thursday's tremor, which the US Geological Survey recorded in the region at the relatively shallow depth of 10km (six miles).

"Now it's a critical moment for the Tangjiashan quake lake, and the most important thing is to ensure there is no casualty of the people," Mr Wen, on his third trip to the disaster zone, was quoted as saying by the official Xinhua news agency.

Grieving parents demand facts Mapping quake zone

Water levels at Tangjiashan had risen to 739 metres (2,440ft) above sea level and the chances of it bursting were increasing, Xinhua said.

Plans are in place to quickly evacuate an estimated 1.3m people who live in the surrounding area if the lake bursts.

More than 250,000 people downstream have already been moved to higher ground.

The level of the lake - which is on the Jian River just above the quake-ravaged town of Beichuan - is still rising, although water has begun seeping out through the debris.

The threat posed by more than 30 quake lakes formed during the earthquake has become one of the most pressing issues in the aftermath of the quake.

Last month's disaster killed more than 69,000 people and left another 18,000 missing and millions more homeless.

Downstream, hundreds of thousands stand ready to flee

The president of the International Red Cross said China would need up to a decade to fully recover.

Meanwhile, the number of special police in the quake zone has nearly doubled to 5,000, Xinhua reported.

Parents whose children died in classrooms during last month's quake have been angrily demanding officials investigate claims of shoddy construction and corruption.

Authorities promised to investigate the school collapses but correspondents say Beijing is becoming increasingly nervous over the grieving parents' protests.