GUIYANG, Dec. 3 -- Four people were killed and more than 30 injured in a pileup involving 12 vehicles in southwest China's Guizhou Province on Tuesday morning, local authorities said.

Six trucks, four cars, a bus and a minivan ran into each other following a collision in heavy fog at about 8 a.m. on a highway in Jianhe County of the Qiandongnan Miao and Dong Autonomous Prefecture, according to the prefecture fire department.

Firefighters are still clearing the road.

An investigation is underway.