A home-made bomb wounded four Bahraini policemen outside a Shiite village, the kingdom's interior ministry said yesterday.
The bomb was "planted by terrorists" near Janabiyah village, west of Manama, the ministry said. It often uses the term to refer to Shiite anti-government protesters.
The device was remotely detonated, the Al Ayam newspaper cited a security official as saying.
Police said that security forces arrested "one terrorist" who had been involved in preparing the bomb that exploded late on Saturday.
Other culprits had been identified and would be arrested.
Earlier this month, a policeman was killed and two others wounded in what security officials said was a terrorist bombing outside a police station in the Shiite village of Sitra, south of the capital.
Shiite-led demonstrators have kept up anti government protests despite a 2011 crackdown, sparking repeated clashes with security forces.
In mid-February, a police officer was killed by a petrol bomb during clashes with protesters, after a teenager was shot dead during a demonstration marking the second anniversary of the launch of the protests.
Bahrain's Shiite-led opposition yesterday criticised the Sunni-ruled government for warning people against joining protests that are planned for next month and named after Egypt's Tamarod rebellion movement.
"The people have the right to protest peacefully" on August 14 to mark the 42nd anniversary of British forces pulling out of the Arabian Gulf kingdom, said the Al Wefaq movement.
Al Wefaq urged the authorities not to use the demonstrations as a pretext to crackdown on the opposition and launch widespread arrests.
"This will not solve the political crisis. The solution is in satisfying the people's aspirations for liberty, social justice and democracy," said the Shiite movement.
Bahrain's interior ministry warned anyone against taking part in "illegal demonstrations and activities that endanger security".
It referred to calls for demonstrations to be held on August 14 under the slogan "Bahrain Tamarod", which means rebellion in Arabic.
The interior ministry warned security forces would "deal with any attempt to disturb security and stability".
At least 80 people have been killed in Bahrain since the protests erupted in 2011, according to the International Federation for Human Rights.