The condition of two of the nine injured was stated to be critical at hospital, Aurangabad Superintendent of Police Daljeet Singh told IANS over telephone. "The driver lost control of the truck due to bad (condition of) the road and the fog," he said.
More than 40 people, comprising of labourers and their families, were travelling on the truck when it overturned into a roadside ditch near Titai Bigha village in Aurangabad, about 150 km from here, the official said.
All those killed were residents of villages in Palamu and Latehar district of Jharkhand and were returning home after harvesting crops in Bihar's Kaimur district.
Bihar Chief Minister Nitish Kumar directed the district magistrate and the superintendent of police to investigate the accident.
"Taking a serious note of casualties of labourers in this accident, the chief minister has ordered ban on ferrying labourers on trucks in the state," an official of the Chief Minister's Office (CMO) said.
The state government has announced a compensation of Rs.50,000 to kin of all victims.