Bahrain's interior ministry says a blast occurred inside a minibus parked near the British Embassy, but there were no immediate reports of serious damage or injuries.
A brief statement posted by the ministry says the explosion occurred in a public parking area near the British diplomatic compound in the capital Manama. Investigators sealed off the area.
Security has been boosted sharply across Bahrain during annual Shiite religious ceremonies. Bahrain's majority Shiites began an uprising in February seeking greater rights from the Gulf kingdom's Sunni rulers.
An independent commission investigating Bahrain's unrest issued a report last month accusing security forces of abuses such as torture against suspected protesters.