Thousands of opposition supporters demonstrated Friday in a Shiite Muslim village near the Bahraini capital, witnesses said, a day after a car bomb wounded four policemen in another Shiite town.
The Sunni-ruled kingdom has been rocked by sporadic violence since its security forces crushed a month of Arab Spring-inspired democracy protests by Shiites in 2011.
On Friday afternoon supporters of the February 14 Coalition youth group demonstrated in the Shiite village of Jad Fahs outside Manama demanding "democratic changes."
Witnesses said thousands of people flooded the streets waving the national flag and shouting slogans against "dictatorship" and an end to "tyranny."
On Thursday night, assailants remotely detonated a bomb planted in a car as a police patrol drove by in the Shiite village of Salha, the interior ministry said.
"Four policemen were slightly wounded" in the explosion, said the ministry, adding that an investigation had been launched to find the perpetrators of the "terrorist act."
Clashes also erupted in other Shiite-populated villages around Manama on Thursday evening when riot police intervened to disperse demonstrations called by the February 14 Coalition, witnesses said.
The protesters hurled firebombs and stones at the security forces, who responded by firing tear gas and stun grenades.
The latest unrest came after the resumption on Wednesday of a national dialogue aimed at ending the Gulf monarchy's political deadlock, following a two-month summer break.
Led by the influential Shiite group Al-Wefaq, the opposition is taking part in the dialogue while keeping up street protests to call for reform.
Bahrain, a strategic archipelago just across the Gulf from Iran, is the home base of the US Fifth Fleet and Washington is a longstanding ally of the ruling Al-Khalifa dynasty.
At least 80 people have been killed in Bahrain since Arab Spring-inspired pro-democracy protests erupted in February 2011, according to the International Federation for Human Rights.