CAIRO -- An unprecedented wave of anti-American violence swept across Africa, Asia and the Middle East on Friday, with protesters angered by an amateurish video that mocks the founder of Islam storming and scorching U.S. embassies in Tunisia and Sudan, ransacking a German embassy in Sudan, and setting a fast food restaurant ablaze in Lebanon.

In all, there were protests in at least 23 nations, stretching from Morocco to Indonesia and from London to Mogadishu, Somalia. At least seven people died from the violence.

The explosion of demonstrations left the Obama administration scrambling both to halt the attacks and to defend its actions in the midst of a hard-fought election campaign where questions of foreign policy had largely taken a backseat. But there seemed to be no way to calm anger over a video clip whose production and dissemination the United States had nothing to do with and whose origins are still largely uncertain.

U.S. officials took pains to separate American policies from the explosion of violence, the worst manifestation of which was the death of the U.S. ambassador to Libya and three other Americans in an attack in Benghazi, Libya, that coincided with Tuesday’s 11th anniversary of the Sept. 11, 2001, terrorist attacks on the United States.

“The unrest we’ve seen around the region has been in reaction to a video that Muslims – many Muslims – find offensive,” White House spokesman Jay Carney told reporters in Washington. “And while the violence is reprehensible and unjustified, it is not a reaction to the 9/11 anniversary that we know of or to U.S. policy.”

“The U.S. government has nothing to do with this video,” State Department spokeswoman Victoria Nuland emphasized during a briefing for reporters.

The worst violence Friday came in Tunisia, where last year’s Arab Spring began with the toppling of President Zine El Abidine Ben Ali, and in Sudan, where, in contrast, Arab Spring protests against the government of President Omar Bashir fizzled rapidly.

In Tunis, Tunisia’s capital, protesters made it inside the U.S. Embassy compound, despite local police use of tear gas and live ammunition to hold them at bay. They set parts of the compound on fire, raised an Islamist flag, smashed windows, and looted computers, phones and other equipment from embassy structures. They then set fire to the American School next door, sending huge plumes of dark smoke over the city, before local police succeeded in pushing them from the compound’s outer perimeter and back into the street.

According to the Tunisian News Agency, two demonstrators were killed and 29 people were injured, including an unknown number of police officers.

Nuland said security forces in Tunis were prepared for a protest, but not the intensity of violence. She said that when demonstrators made it through an exterior perimeter, Tunisia’s presidential guard was sent in and controlled the situation. A secure inner perimeter protected by American security was not breached, she said, and no Americans were injured.

In Sudan, an estimated 5,000 protesters descended on the German Embassy in central Khartoum after Friday prayers, breaking in and setting part of the building on fire. Police used tear gas in an effort to break up the demonstration, but the protesters moved on to the nearby British Embassy, where they threw rocks but were unable to enter the building.