The bullet proof car in which Mahanta, who has Z plus security cover, along with his son Subham was travelling from Guwahati to Nagaon town, hit the truck near Bebejia.
All the four occupants of the car - Mahanta, his son, NSG cadre Dinesh Singh and driver Birendra Singh - were injured and they were admitted to a private hospital here.
Noting both the AGP leader and his son were reported to be out of danger, the police said Mahanta received injured in both his legs and face.