A low intensity explosion took place close to the stage where Bihar Chief Minister Nitish Kumar was present for a programme in Nalanda district of the state.
The chief minister is unhurt.
According to media reports, the blast took place nearly 20 feet away from the stage. One person has been arrested in connection with the incident.
The police recovered a firecracker and a matchbox from the accused.
A case has been registered and further probe is underway.