Nine live bombs were recovered and defused by the National Investigation Agency (NIA) in collaboration with state police in the Jharkhand capital late Monday, police said.
The bombs were recovered from the room of a private student lodge in the Hindpidi area of Ranchi.
The student who lived in the room in which the bombs were found was missing, and no arrests have been made in this connection.
Director General of Police Rajiv Kumar said investigations were on in the case, and the police had acted on a tip-off.