The explosion in Karzakan killed a Bahraini and slightly wounded an Asian national, the interior ministry said, describing it as a "terrorist" attack.
Late last night a policeman was killed in a separate attack in Damistan, a nearby Shiite village, the authorities said.
It was the first deadly attack on the security forces since parliamentary elections in November that were boycotted by the main Shiite opposition group, which is calling for democratic reforms in the Sunni-ruled kingdom.
Small but strategic Bahrain, home to the US Navy's Fifth Fleet, remains deeply divided three years after the month-long demonstrations.
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Protests still frequently break out in Bahrain's Shiite villages, sometimes sparking clashes with police.
The main opposition Al-Wefaq movement quickly distanced itself from the Damistan attack, stressing its "rejection" of violence.
Attacks against the security forces have increased this year, with three policemen -- including one from the UAE -- killed in a bomb attack in a Shiite area on March 3.