"An act of terrorism targeted a police bus on Khalifa bin Salman highway" the ministry's Twitter account said.
The ministry said the attackers used "homemade bombs" and that they were detonated remotely.
Pictures of the targeted bus showed shrapnel all over the vehicle. The injuries to the policemen were described as "medium to severe."
Sunni-ruled Bahrain accuses Shiite Iran of inciting unrest on its territory, an accusation that Tehran denies.
Home to the US 5th Fleet, the small Gulf monarchy of Bahrain has seen an uptick in violence since 2011, when mass protests led by the country's Shiite Muslim majority erupted in demands for wider reforms from the ruling Sunni family.
The protests were quelled with the help of regional Sunni powers, led by Saudi Arabia.
The government denies discrimination against Shiites.
The ministry said the attackers used "homemade bombs" and that they were detonated remotely.
Pictures of the targeted bus showed shrapnel all over the vehicle. The injuries to the policemen were described as "medium to severe."
Sunni-ruled Bahrain accuses Shiite Iran of inciting unrest on its territory, an accusation that Tehran denies.
Home to the US 5th Fleet, the small Gulf monarchy of Bahrain has seen an uptick in violence since 2011, when mass protests led by the country's Shiite Muslim majority erupted in demands for wider reforms from the ruling Sunni family.
The protests were quelled with the help of regional Sunni powers, led by Saudi Arabia.
The government denies discrimination against Shiites.