Security forces with tanks have overrun a square in the centre of Bahrain's capital Manama where anti-government protesters have been camped for weeks. At least three died after police fired on mainly Shia protesters, reports say. State TV said two police died. There are reports that troops are shooting at people and threatening doctors at the main Salmaniya hospital. The country's Sunni rulers have declared martial law and called in Saudi troops to help keep order. At least two people died in clashes on Tuesday and more than 200 were injured.