Violence spreads across Middle East over anti-Islam film Anti-American protests have erupted in the Middle East over a crudely made film mocking the prophet Muhammad, resulting in violent embassy protests around the Middle East and heightened security at U.S. facilities abroad. U.S. officials are bracing for possible protests across the Muslim world over an anti-Islam film blamed on the attack in Libya that killed a U.S. ambassador and three other Americans. With angry protests already occurring in Egypt and Yemen, the U.S. has put all of its diplomatic missions on high alert. And Secretary of State Hillary Rodham Clinton has denounced the anti-Islam video in hopes of pre-empting further turmoil. In Libya on Tuesday, the storming of the U.S. Consulate in Benghazi killed the American ambassador, Chris Stevens, and three other embassy staff members. Libyan officials say the attack in Benghazi was a planned operation by heavily armed militants that may have been timed to mark the 11th anniversary of the 9/11 terror attacks on the U.S. and that the militants used civilian protesters as cover for their action. In Egypt, angry youths climbed the walls of the U.S. Embassy on Tuesday in Cairo and brought down the flag. Protesters clashed Thursday with police near the U.S. Embassy. Police used tear gas to disperse he protesters and the two sides pelted each other with rocks. But unlike Tuesday, when protesters climbed the embassy's walls and several of them breached its grounds, police kept the protesters away from the compound. The Health Ministry said 224 people, including policemen, were wounded, but they mostly suffered light injuries. Twelve protesters have been arrested. The clashes continued well into the night. In Yemen's capital of Sanaa, hundreds of protesters chanting "death to America" and "death to Israel" stormed the U.S. Embassy compound and burned the American flag on Thursday. Yemen's president, Abed Rabbo Mansour Hadi, quickly apologized to the U.S. and vowed to track down the culprits, just as Libya's president did. Egypt's Islamist President Mohammad Morsi, who had been slow to speak out on Tuesday's assault on the embassy in Cairo, promised Thursday that his government would not allow attacks on diplomatic missions. In Iraq, several hundred Shiite hardliners protested Thursday in Baghdad's Shiite stronghold of Sadr City, and the leader of an Iranian-backed Shiite militia, Asaib Ahl al-Haq, threatened anti-U.S. attacks. And in Iran, about 50 protesters shouted, "Death to America" outside the Swiss Embassy, which looks after U.S. interests there. Riot police kept the crowd at bay. The U.S. State Department said via Twitter that Kuwait, Jordan, and Oman would be on alert for possible protests: Travel - State Dept @TravelGov #Travel #Kuwait possible protests in front of the US embassy Kuwait over the next few days, incluidng this evening at approximately 8 pm. Travel - State Dept @TravelGov #Travel #Jordan possible demonstrations near the embassy this evening & tomorrow. #AmCits should exercise caution & enroll in STEP for info. Travel - State Dept @TravelGov #Travel #Oman demonstrations have begun in front of US Embassy Musct. #AmCits should exercise caution & enroll in STEP for more info. Click for more from the State Department on Twitter. President Barack Obama ordered increased security at American embassies and consulates around the world Thursday following the attack and urged its citizens abroad to be vigilant. His administration sent two warships to the Libyan coast, ready to respond to any mission ordered by the president, and 50 Marines were sent to the Libyan capital of Tripoli to help with security. Obama told voters campaigning Thursday in Colorado that the Benghazi Consulate killers will be brought to justice and that protecting Americans serving abroad is one of his highest priorities. The spreading violence comes as outrage grows over a movie called "Innocence of Muslims" produced by anti-Islam campaigners in the U.S. that mocked Islam's Prophet Muhammad. The amateurish video was produced in the U.S. and excerpted on YouTube. It depicts Muhammad as a fraud, a womanizer and a madman in an overtly ridiculing way, showing him having sex and calling for massacres.