Aftershock near China quake lake

Mapping the quake zone In pictures: Draining the lake

A strong aftershock in south-west China has rocked a lake formed by a recent earthquake that has been threatening to burst its banks, state media reported.

The 20-second, magnitude five aftershock caused landslides on mountains near the Tangjiashan lake.

Soldiers have dug a diversion channel to help drain the lake and 250,000 people have been evacuated from the area since a devastating 12 May tremor.

The lake threatens to flood about one million people in the disaster zone.

Experts had warned the lake could burst at any time, sending millions of cubic metres of water down river valleys.

The lake's water-level was continuing to rise dangerously on Sunday despite the drainage channel, Xinhua reported.

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.

Government figures put the quake death toll at 69,130 with another 17,824 people missing.