Chief EU diplomat Catherine Ashton strongly condemned the attacks on Western diplomatic missions in several Muslim countries and urged the local authorities to ensure their security.

"I have been following the development with great concern and urge the national authorities of the affected countries to quickly ensure the safety of diplomatic missions and to protect diplomatic personnel," she said in a statement to RIA Novosti.

Riots erupted across the Muslim world this week in response to an American anti-Islam video, "Innocence of Muslims," posted to the Internet on Tuesday, the 11th anniversary of the September 11, 2001 attacks on the World Trade Center in New York City.

U.S. Ambassador to Libya Christopher Stevens and three others were killed in Benghazi on Tuesday in one of the first of several such riots, which have since spread to Tunisia and Sudan, among other predominantly Muslim countries.

About 5,000 rioters also attacked the Embassies of Germany and the U.K. in the Sudanese capital of Khartoum.