Two policemen were severely wounded by a homemade bomb west of Bahrain's capital Manama, Bahrain's Interior Ministry has said in a message on its Twitter account.
The policemen were attacked late on Friday in al-Bade'e street near al-Maqsha'a village in what the ministry said was "a terror act." It gave no further details.
Bahrain, home of the US Fifth Fleet, has been buffeted by political turmoil since 2011 when mostly Shia protesters took to the streets calling for political reforms and more say in the Sunni ruled island kingdom.
The Bahraini government largely put down the uprising with help from Gulf Arab neighbours but small-scale clashes continue and bomb attacks mainly on policemen and security officers have been increasing since mid-2012.