The incident happened while the car of Ivo Tadic, an HDZ BiH deputy to the Zenica cantonal assembly, was parked in a parking space outside the building housing the cantonal institutions.
The low-power explosive device went off when Tadic entered his car and tried to start the car after he attended the assembly's session. The blast caused minor damage to the vehicle.
The police conducted an on-site investigation.
The HDZ BiH condemned the incident, labelling it as an act of terrorism. The party said that recently its officials had been receiving treats in areas predominantly populated by Bosnian Muslims (Bosniaks).