GUIYANG - Seven people were killed and more than 20 others injured Monday evening after a pile-up involving 14 vehicles in Southwest China's Guizhou province, said local authorities Tuesday.

The accident occurred about 6 pm at a section of an expressway in the city of Duyun in Bouyei-Miao Autonomous Prefecture of Qiannan, according to a spokesman with the prefecture's government.

Five people were killed at the scene, while the other two died at a hospital after emergency aid failed, said the spokesman, adding that the injured were being treated at the hospital.

Police are investigating the cause of the accident.