Bahrain police found a bomb planted on a busy causeway linking the island to Saudi Arabia, and four officers were shot and wounded in a village, officials said in the latest violence to hit the kingdom on the second anniversary of its uprising.
The 2 kg bomb, discovered on Thursday near a mosque on the Bahraini end of the route used by thousands of people a day, was safely defused, said the Information Authority in the U.S.-allied Gulf Arab state.
Late on Friday, four officers were hit by birdshot pellets in the Shi'ite Muslim village of Karzakan, the authority added, quoting the island's chief of public security Major-General Tariq Hassan al-Hassan.
The announcements came as thousands were expected to take to the streets of the capital on Saturday for the funeral of a teenager the opposition said was killed in clashes between police and activists earlier this week.
The violence has cast a shadow over talks launched this week between mostly Shi'ite Muslim opposition groups and the Sunni Muslim-dominated government to try to end political deadlock in Bahrain, home to the U.S. Fifth Fleet.
Bahrain has seen almost daily demonstrations in the run-up to the anniversary of the pro-democracy revolt, which has put the kingdom on the front line of a region-wide tussle for influence between Shi'ite Muslim Iran and Sunni Arab states such as Saudi Arabia.
Bahrain accuses Iran of stirring up trouble in the kingdom, which Tehran denies.
Mass protests that erupted in February 2011 at the height of the Arab Spring were crushed, but demonstrations demanding greater rights for Bahrain's Shi'ite majority and an end to the absolute power of the Sunni ruling family have continued.
Thousands took to the streets again on Friday, leading opposition group al-Wefaq said on its website, with clashes breaking out with security forces in several villages and districts.