As Americans marked the tenth anniversary of the September 11 terror attacks on Sunday, extremist Muslims in the United Kingdom protested outside the U.S. Embassy in London and set fire to the American flag.

The protest was taking place as commemoration services for the terror attacks were being held in London. 

Some of the radicals were part of a group called Muslims Against Crusades. During their protest they chanted anti-American slogans, such as "USA terror state," "Democracy go to Hell" and "Down down U.S.A."

According to a report in the Digital Journal, moderate groups of Muslims were also on hand to oppose the extremists' view. According to the report, the moderates held up signs reading, "If You Want Sharia, Move to Saudi."

Arabs in the Gaza Strip also danced on September 11, 2001, as the World Trade Center was on fire after Al-Qaeda terrorists slammed two planes into the towers. Jerusalem Mayor Nir Barkat recalled this in a 9/11 memorial ceremony on Sunday.

"At the end of the horrific day, after watching the horror unfold, I remember the shock on the faces of people around me when we watched people dancing for joy in the streets of Gaza while New York was on fire," Barkat said.

"Then I realized that September 11 was the day on which Islamic terrorism was no longer an exclusive Israeli challenge. It became global in a big, big way," he added.

Meanwhile, the Taliban "celebrated" the anniversary of 9/11 by blowing up a truck in Afghanistan, killing five Afghans and wounding 77 American soldiers. One of the casualties was a three-year-old girl.

On Friday, Egyptian mobs attacked the Israeli Embassy in Cairo, where the besieged Israeli secuity staff was rescued by Egyptian commandos.