(CNN) -- Global reaction to the attacks on U.S. diplomatic missions in Egypt and in Libya, where U.S. Ambassador Chris Stevens and three other Americans were killed amid Muslim outrage over a film mocking the Prophet Mohammed:
U.S. President Barack Obama:
"Today we mourn four more Americans who represent the very best of the United States of America. We will not waver in our commitment to see that justice is done for this terrible act. And make no mistake, justice will be done."
Mohammed al-Megaryef, president of Libya's ruling General National Congress:
"We apologize to the U.S., to the American people and to the government and also to the rest of the world for what happened yesterday. And at the same time, we expect the world to cooperate with us to confront to what is meant out of this kind of act of cowardice."
Egyptian Prime Minister Hesham Kandil:
"What happened at the U.S. Embassy in Cairo is regrettable and rejected by all Egyptian people and cannot be justified, especially if we consider that the people who produced this low film have no relation to the U.S. government. We ask the American government to take a firm position toward this filmmakers within the framework of international charters that criminalize acts that stir strife on the basis of race, color or religion."
"The office of the president of the Islamic Republic of Afghanistan strongly and resolutely denounces this desecrating act and declares its serious abhorrence in the face of such an insult. Prophet Mohammed ... was the greatest prophet of Islam, a prophet sent to guide mankind, a pacifist and a promoter of truth and honesty in the universe. In fact, insult to the greatest Prophet of Islam means insult to high values of 1.5 billion Muslims across the world. This offensive act has stoked interfaith enmity and confrontation and badly impacted the peaceful coexistence between human beings."
U.S. Secretary of State Hillary Clinton:
"Some have sought to justify this vicious behavior, along with the protest that took place at our embassy in Cairo yesterday, as a response to inflammatory material posted on the Internet. America's commitment to religious tolerance goes back to the very beginning of our nation. But let me be clear, there is no justification for this -- none. Violence like this is no way to honor a religion or faith and as long as there are those who would take innocent life in the name of God, the world will never know a true and lasting peace."
British Foreign Secretary William Hague:
"There is no justification for such an attack and the appalling death of a U.S. official. My thoughts and condolences are with his family and all his colleagues at the State Department. I welcome President Megaryef's condemnation of this incident. It is essential that the Libyan authorities take urgent action to improve security, particularly in Benghazi, and identify those responsible for such attacks."
U.S. Sens. John McCain, Lindsey Graham and Joe Lieberman:
"Despite this horrific attack, we cannot give in to the temptation to believe that our support for the democratic aspirations of people in Libya, Egypt, and elsewhere in the broader Middle East is naive or mistaken. We cannot resign ourselves to the false belief that the Arab Spring is doomed to be defined not by the desire for democracy and freedom that has inspired millions of people to peaceful action, but by the dark fanaticism of terrorists. To follow this misguided path would not only be a victory for the extremists and their associates, but a betrayal of everything for which Chris Stevens and his colleagues stood and gave their lives."