The decision re-imposes a state of emergency-style rules in the Sunni-ruled nation, whose Shi'ite majority launched an uprising over 20 months ago, aiming to win a greater political voice.

The announcement by the Interior Ministry did not say what actions could be taken against protests, but suggests Shi'ite political groups could face arrests or formal closures of their offices.

Emergency rules, including curfews and special military tribunals, had been enacted for several months during the early stages of the uprising, which has left more than 50 people dead.