Protesters storm US Embassy in Yemen

President Hamid Karzai canceled an official visit to Norway and spoke by phone with U.S. President Barack 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.

Stevens was the first U.S. ambassador killed in the line of duty in 30 years.

The movie, "Innocence of Muslims," came to attention in Egypt after its trailer was dubbed into Arabic and posted on YouTube. The video-sharing website blocked access to it Wednesday. The trailer depicts Muhammad as a fraud, a womanizer and a madman in an overtly ridiculing way, showing him having sex and calling for massacres.

Associated Press writers Slobodan Lekic in Brussels and Lara Jakes in Baghdad contributed to this report.