"The bomb squad arrived at the scene to secure the area but the bomb exploded, causing damage to the mosque," the ministry said in a statement.
The explosion appeared to rip through the bathroom and partially destroy the roof of the Muqsha village mosque, west of the capital Manama, according to a photograph published by the ministry. No casualties were reported.
Seven people suspected of involvement in deadly bombings targeting Bahrains security forces were apprehended, the public prosecutors office said on its Twitter page on Monday.
Bahrain, which is home to the U.S. Navys Fifth Fleet, was swept by unrest during the 2011 "Arab Spring" uprisings when the majority Shiites demanded political reforms.
Since then, there have been sporadic protests and a growing number of attacks using explosives, Reuters reported.
The prosecutors office said it had interrogated and remanded into custody "a terrorist cell that specialised in explosive projectiles and devices that can be detonated from afar".
The suspects were involved in two bombings in as many days in December that killed a policeman and a civilian, the prosecutor said.
The office did not disclose when the group was arrested, who its members were or when they might face trial.