Demonstrators attacked the U.S. embassies in Yemen and Egypt on Thursday in protest at a film they consider blasphemous to Islam, and American warships headed to Libya after the U.S. ambassador there died in related violence earlier this week. Hundreds of Yemenis broke through the main gate of the heavily fortified compound in the capital Sanaa, shouting “We sacrifice ourselves for you, Messenger of God”. They smashed windows of security offices outside the embassy and burned cars. “We can see a fire inside the compound and security forces are firing in the air. The demonstrators are fleeing and then charging back,” one witness told Reuters. A security source said at least 15 people were wounded, some by gunfire, before the Yemeni government ringed the area with troops. An embassy spokesman said its personnel were safe. In Egypt, protesters hurled stones at a police cordon around the U.S. embassy in central Cairo after climbing into the embassy compound and tearing down the American flag. The state news agency said 13 people were hurt in violence which erupted late on Wednesday, following initial protests on Tuesday. During a similar protest on Tuesday at the U.S. consulate in Benghazi, Libyan Islamists staged military-style assaults on the mission and a safe house refuge. It was the 11th anniversary of al Qaeda’s attacks on the United States on September 11, 2001. The U.S. ambassador Christopher Stevens and three other Americans died in the assaults, carried out with guns, mortars and grenades. Eight Libyans were injured. President Barack Obama vowed to “bring to justice” those responsible for the attack, which U.S. officials said may have been planned in advance. Secretary of State Hillary Clinton said Washington had nothing to do with the video, which she called “disgusting and reprehensible”. The U.S. military moved two destroyers towards the Libyan coast, in what an official said was a move to give the administration flexibility for any future action against Libyan targets. The U.S. military also dispatched a Marine Corps anti-terrorist team to boost security in Libya, whose leader Muammar Gaddafi was ousted in a U.S.-backed uprising last year. Obama said security was being increased at U.S. diplomatic stations around the globe and on Thursday the U.S. consulate in Berlin was partially evacuated after an employee fell ill on opening a suspicious envelope. Bangladeshi Islamists tried to march on the U.S. embassy in Dhaka and Iranian students protested in Tehran outside the Swiss embassy, which looks after U.S. interests because Washington and Tehran have no diplomatic relations. Earlier in the week, there were protests at U.S. missions in Tunisia, Sudan and Morocco.