"They can harm and hit the enemy much easier than we can," the Italian news agency Agenzia Giornalistica Italia quoted the al-Qaida organization in Yemen as saying.
Al-Qaida's call for a "crusade" against American diplomats was in reaction to a crude, low-budget film produced in the United States that made a mockery of the Prophet Muhammad, the founder of Islam.
"Whoever meets American ambassadors or envoys, should follow the example of the Libyans who killed the American ambassador," the terrorist organization said. "The film published in America smears our prophet Muhammad, peace be with him, and is part of a never ending crusade against Islam."
Violent protests have broken out in numerous Muslim countries since an attack on the U.S. Consulate in Libya left four Americans dead, including U.S. Ambassador Christopher Stevens