Bahraini authorities detained at least six prominent opposition leaders on Thursday, a day after three police and three protesters died in clashes.
Among those arrested overnight were Haq leader Hassan Mushaima and Wafa leader Abdel Wahhab Hussein, who called to topple the royal family, Wefaq said.
Also arrested was Ibrahim Sharif, head of the secular leftist party Waad.
A medical source told Reuters scores of people were taken to Bahrain International Hospital on Wednesday, hit by rubber bullets or shotgun pellets or suffering teargas inhalation.
Demonstrators threw rocks and petrol bombs at the security forces who were trying to clear the protest camp and killed three by running them over with their cars, witnesses and medical sources said.
