The robbers, said to be 10 in number, intercepted a bus belonging to Kumar Travels at gun point and looted jewellery, valuables, mobile phones and other belongings from passengers, Rajaul police station in-charge Shivkumar Yadav said.
A case has been lodged in this connection by the bus driver, he said, adding a probe was on in the matter.
The private bus was carrying passengers to Purnia from Jamshedpur in Jharkhand, Yadav said.