Attackers threw Molotov cocktails at a police patrol north of Bahrain's capital on Saturday, killing one officer and critically injuring two others, the interior ministry said.
The attack took place in the neighborhood of Karbabad outside Manama, the ministry said on its Twitter account, calling the unknown assailants a "terrorist group."
Bahrain, which hosts the US Fifth Fleet, has reported a growing number of attacks using home-made explosives in the last two years and has accused Iran and its allies in the Shi'ite Lebanese militant group Hezbollah of sponsoring the plots.
The Gulf Arab state has experienced sporadic unrest since mass protests in 2011 led by majority Shi'ite Muslims demanding more rights and reforms and a bigger role in the Sunni-led government.
Security forces put down the protests by force and launched a crackdown on dissent, arresting opposition leaders for incitement and revoking the citizenship of more than 300 people.
The kingdom's police chief told Reuters in February the country was slowly returning to stability five years later, but still faced security threats from Iran-backed elements and militants linked to Islamic State.