Obama says in a speech Tuesday before the United Nations General Assembly that "there are no words that excuse the killing of innocent" and "no video that justifies an attack on an embassy." He added that the United States will not shrink from its role with nations under transition, despite the violence.

Obama says the video "is an insult not only to Muslims, but to America as well."

Obama is challenging the international community to confront the root causes of turmoil in the Middle East, saying the world faces "a choice between the forces that would drive us apart and the hopes we hold in common."

Four Americans were killed in Libya, including U.S. Ambassador Chris Stevens, along with more than 50 others in the violence.

Obama also told the assembly that he wants to resolve the dispute over Iran's nuclear program through diplomacy but that the time to do that is not unlimited.

Obama says that time after time, Iran has failed to demonstrate that its nuclear program is peaceful and has failed to meet its obligations to the United Nations. He also says the Iranian government has been propping up the dictatorship in Syria and supporting terrorist groups abroad.

The President says, quote, "the United States will do what we must to prevent Iran from obtaining a nuclear weapon."

This is Obama's final international address before the November elections.