HEFEI, Nov. 15 (Xinhua) -- At least 18 people were killed on Wednesday in an expressway pile-up involving dozens of vehicles in east China's Anhui Province, local traffic police said.

Over 30 vehicles collided in fog around 7:45 a.m. on an expressway section in Fuyang City, leaving 18 people dead and 19 injured.

The injured are being treated in hospital, nine of whom are in a serious condition.

Several vehicles caught fire and the accident caused three to four km's traffic congestion.

Over 20 fire fighting trucks were dispatched to the scene, and the fire was extinguished at 10:38 a.m.

An investigation into the accident is ongoing.