SANAA, Yemen (USA TODAY) -- American unrest escalated in the Middle East on Thursday as demonstrators burned U.S. flags in Yemen and protesters descended on the embassy in Cairo for a third straight day.
Security was increased at American embassies and consulates around the world.
In Yemen's capital of Sanaa on Thursday morning, black smoke billowed into the sky from burning SUVs inside the U.S. Embassy compound. Hundreds of angry demonstrators tried to storm the building, chanting "death to America" and death for the American filmmaker who made an anti-Islam film that helped spark a deadly attack on the embassy in Libya and protests in Egypt.
Protesters marched on the embassy from three sides before being blocked by Yemeni security forces. Some demonstrators were able to breach the security cordon before eventually being pushed back by troops firing tear gas and live ammunition into the air.
"They brought this on themselves," Abdullah Rahman Safi shouted above the sound of gunfire. "We want to close the American embassy for this insult on prophet Mohammed," he added, referring to the film Innocence of Muslims posted on YouTube depicting the Islam prophet Mohammed as a fraud and a womanizer.
More aggressive demonstrators also shouted "Death to America," targeting American ambassador to Yemen, Gerald Feierstein.
Secretary of State Hillary Rodham Clinton sharpened her criticism of the film Thursday calling it "disgusting and reprehensible" and a cynical attempt to offend people for their religious beliefs.
But Clinton said the U.S. would never stop Americans from expressing their views, no matter how distasteful. She said the film is no justification for violence or attacks on U.S. diplomatic facilities and personnel.
Clinton said Thursday the U.S. is monitoring protests in Yemen.
Yemeni President Abed Rabbo Mansour Hadi apologized to President Obama for the attack on the embassy and ordered an investigation. The Yemeni Embassy in Washington condemned the attack and vowed to ensure the safety of foreign diplomats and to step up security measures around their missions in the country.
It was similar to an attack on the U.S. Embassy in the Egyptian capital on Tuesday night. A mob of Libyans also attacked the U.S. consulate in the eastern city of Benghazi, killing American Ambassador Christopher Stevens and three other Americans.
Attorney General Eric Holder, in Doha, Qatar on Thursday for the Arab Forum on Asset Recovery, said the FBI opened an investigation into the attack.
Yemen is home to al-Qaeda's most active branch and the United States is the main foreign supporter of the Yemeni government's counterterrorism campaign. The government on Tuesday announced that al-Qaeda's No. 2 leader in Yemen was killed in an apparent U.S. airstrike, a major blow to the terror network.
U.S. officials also were investigating whether the rampage in Libya was actually planned to coincide with the anniversary of the 9/11 terror attacks.
Egyptian protesters clashed Thursday with police near the U.S. Embassy in Cairo for the third day in a row. Police used tear gas to disperse the protesters and the two sides pelted each other with rocks.
But unlike Tuesday, the police kept the protesters away from the embassy's compound.
The Interior Ministry, which is in charge of police, said 16 protesters and 13 policemen were wounded in the clashes, which broke out overnight and were ongoing. Twelve protesters have been arrested, it said.
The protests were going on around the Tahrir Square area -- the heart of last year's revolution that led to the ouster of dictator Hosni Mubarak and close to the U.S. Embassy. Protesters were initially primarily hard-line Muslims, but since Wednesday evening the composition of the crowd seemed to change and police battled young men aligned with a group called "Ultras" -- comprised of soccer fans who are growing more political.
President Mohamed Morsi, Egypt's first Islamist president elected in June, is teetering between allowing freedom of expression and maintaining stability as nations worldwide adjust to power shifts propelled by the Arab Spring. Morsi, speaking while on a visit to Brussels, vowed on Thursday not to allow attacks on foreign embassies in Cairo, saying the Egyptian people reject such "unlawful acts."
In Yemen, demonstrators gathered in the streets around the embassy compound chanting: "We will not leave until the Americans leave" as they burned tires in front of soldiers and water cannon trucks.
Sustained gunfire rang out as troops attempted to disperse the crowds, with AK-47s and .50-caliber machine guns being fired over the heads of the chanting crowds. Medics on the scene said one man sustained a head wound from a falling bullet.
Security had been stepped up on the approach roads to the embassy building in anticipation of protests following similar attacks in Libya and Egypt. Soldiers stood back allowing protesters through the concrete roadblocks toward the U.S. Embassy building and some marched alongside the demonstrators, before shots were fired over their heads by armored vehicles and other foot soldiers.
The streets surrounding the U.S. Embassy in the northeast of the capital remained tense for several hours after the initial storming of the compound.
Embassy staff have been living in Sanaa's Sheraton hotel, just a few hundred meters from the embassy building, since violence broke out during political unrest in the city last year. It was unclear how many staff were in the embassy when the compound was stormed.
Troops responsible for security around the U.S. Embassy are from Yemen's Central Security Forces, commanded by Brigadier General Yahya Saleh, nephew of former president Ali Abdullah Saleh. Saleh finally relinquished power last February after a year-long uprising against him.
As part of recent structural changes within the military, under the terms of a U.S.-backed political transition deal, Yemen's new president, Abdu Rabu Mansor al-Hadi, has moved several members of the Saleh family from key army and air force positions.
In Iraq on Thursday, hundreds of Shiite followers of the anti-American cleric Muqtada al-Sadr demanded the closure of the U.S. Embassy in Baghdad because of the film. Protesters burned American flags and carried banners reading, "We reject the attack on the prophet Mohammed."
"No, no, to Israel! No, no to America!" thousands shouted in the Shiite stronghold of Sadr City in northeast Baghdad. "Yes, yes for Messenger of God."
Afghanistan's government, meanwhile, sought to avert any protests as past anger over perceived insults to Islam has triggered violence in the country.
President Hamid Karzai canceled an official visit to Norway and spoke by phone with President Obama to convey his condolences for the deaths of the U.S. ambassador to Libya and three other diplomats, a statement said. He also discussed the "film and the insulting of holy Islamic values," but the statement provided no other details.
Analysts say they don't believe the tragedy in Libya will impact its relationship with the current U.S. administration.
"It's a very good and strong relationship," said Paul Salem, director of the Carnegie Middle East Center in Beirut. "In general, the view of the U.S. after the revolution was a fairly positive image among most Libyans."
But the region retains its challenges.
"The Middle East is now going to be the wild Middle East in some ways and this kind of shoot em up action is, I am afraid, going to be part of the political landscape in the Middle East for some time to come," said Joshua Landis, director for Middle Eastern Studies at the University of Oklahoma. "We've got to brace ourselves."