An earthquake that struck the remote Chinese province of Qinghai is now known to have killed almost 600 people and injured thousands. The tremor wrecked the town of Jiegu. The BBC correspondent in the province says cold and rain are hampering relief operations. A local teacher told the BBC's Chinese service that almost all residential housing in Jiegu had collapsed, and so had its school.

The extents of the destruction of houses is very bad. More than 80% of the residential houses built with mud and brick have collapsed. And many people have been buried or trapped underneath. We are now helping people to carry out rescues on their own, but we lack heavy lifting equipment.