Pro-regime supporters wielding knives and sticks attacked residents of Bahrain's villages overnight, witnesses and the opposition said on Wednesday.
Dozens of pro-regime thugs – nicknamed locally by activists as the Baltajiya – appeared at the Alba Roundabout on the outskirts of the capital Manama and entered a number of predominantly Shia villages.
Al-Wefaq, the largest Shia opposition group, said the attackers were in civilians clothes and "beat up" residents.
"The security forces did not carry out their duty, they did not disperse the (assailants) or prevent them from attacking citizens," the statement said, adding that authorities must "deal with these militias."
Activist Ala'a Shehabi said the Baltajiya were operating in conjunction with the police.
"They appear alongside the police and the police don't really treat them with hostility – there is a sense of familiarity between the two," she said.