Clashes have continued overnight in Bahrain's capital, Manama.
Security forces fired tear gas and stun grenades at protesters gathering ahead of the first anniversary of the start of pro-democracy demonstrations in the Gulf kingdom, reports the BBC.
Thousands of people are expected to march on Pearl Roundabout, which was the focus of protests last year.
Many of the demonstrators are from the Shia majority, who want greater democracy in the Sunni Muslim-led kingdom.
At least 60 people have been killed since the uprising began last February.
Riot police and other security forces have been deployed across Bahrain in response to the latest protests.