Landslides and flooding triggered by heavy rain have killed at least 127 people in China's Gansu province.

Chinese Premier Wen Jiabao has flown to the scene, and said no effort should be spared to rescue those who might still be alive.

The landslides began at about midnight, blocking the river running through Zhouqu, a town largely populated by Tibetans.

The river eventually burst its banks upstream and sent waves several storeys high crashing into the town.

Buildings were swept away, vehicles were buried, and - according to state media - some 2,000 people are missing in Zhouqu.

Security forces and medical teams have been sent to help.

Local officials say the mud, more than a metre thick in some places, is hampering rescue efforts.