also violent clashes in several mainly Shia areas. In the village of Sitra the police fired on residents. A doctor told the BBC News that soldiers and police were using ambulances to attack people. Britain advised their nationals in Bahrain to leave as soon as possible and promised to help anyone who needed evacuation. "We advise against all travel to Bahrain; we recommend those who do not have a pressing reason to remain should leave by commercial means as soon as it is safe to do so." the British Foreign Office said. 16–17 March Following the deployment of the Peninsula Shield Force , security forces launched a crackdown on protesters at the Pearl Roundabout and elsewhere. Security forces used armored vehicles and helicopters during the operation, and fired tear gas to disperse protesters. Hundreds of protesters were cleared from Pearl Square. Five protesters were killed and dozens wounded during the crackdown. Many activists were also arrested or re-arrested. The Royal Bahraini Army warned that gatherings should be avoided "for your own safety". The Saudi presence also fueled concerns of further strife over the Sunni-Shia divide. The following day, Manama was reported to be largely quiet. Shops and malls were still shut as soldiers were stationed throughout the city, including downtown commercial districts and the Bahrain Financial Harbour. Some clashes continued outside Manama in places such as Sitra and Karrana. Salmaniya Hospital also reported that it was running short of medical supplies such as sterilisation equipment and oxygen tanks. Government forces also blocked off the hospital trapping in at least 100 doctors who were unable to leave the premises. Other physicians were forcibly removed and detained. Physicians for Human Rights reported that Bahraini security forces tortured patients in attempt to extract confessions of anti-government activity. One teenage patient, who had been wounded with birdshot and blinded in one eye days before, said that he was stripped naked, photographed, and beaten with the batons of masked security forces. Bahrain TV aired coverage of South Asian expatriate workers being dragged out of an ambulance at the hospital while being assaulted by protesters. At least six people were also reported killed. Several opposition leaders and activists were arrested overnight, including Hassan Mushaima; Ibrahim Sharif, the head of the Waad political society; and Abdul Jalil al-Singace, a leader of the Haq movement. Mushaima also spoke to Al Jazeera saying: "[Bahraini security forces] should stop killing