Investigation showed overloading was the main cause of the traffic accident that left 19 dead and 13 injured in north China's Hebei Province, police said Sunday.

A truck ran into the rear of another vehicle and then rushed into a roadside crowd Thursday evening in Zhaozhuangzi village of Yangliuzhuang town in Luanxian county, leaving 19 dead and 13 injured.

The driver and the owner of the truck have been held in police custody.

Police also said the driver took inappropriate actions to slow down the truck on a crooked and slope road.

All the injured have been taken to nearby hospitals. Of them, seven, who suffered from more severe injuries, have been admitted to a better hospital, the Tangshan No. 2 Hospital.

The seven, aged between 3 and 59, are recovering from their fractures and scratches, doctor Zhang Shuyan said.

Traffic police in Tangshan, which administers Luanxian, have stepped up checks on overloading of vehicles in the wake of the fatal accident.