An explosion wounded a policeman in a Shiite village near Bahrain's capital, where protesters demonstrating against the ruling Sunni monarchy had blocked roads, the interior ministry said.
Clashes frequently erupt on the outskirts of Manama between security forces and protesters from the country's Shiite majority demanding Bahrain's ruling Sunni Khalifa family surrender its grip on all key cabinet posts in favour of an elected government.
"Police had confronted a group of saboteurs who blocked roads in the village of Akr al-Sharqi," the ministry said in a statement late Sunday.
A policeman trying to "help a woman cross a road" was "lightly wounded" in the explosion, which damaged a police vehicle and a civilian vehicle, the statement said, without giving further details.
Arab Spring-inspired protests backed by Bahrain's Shiite majority began in mid-February 2011 and were brutally crushed a month later.
The International Federation for Human Rights says at least 89 people have been killed since the uprising broke out.
Last year authorities increased the penalties for those convicted of violence, introducing the death penalty or life sentences in cases which resulted in deaths or injuries.