This isn't BBC news special report. Good morning I'm George Stephanopoulos let's -- right the State Department Hillary Clinton about to speak on the death of the US ambassador in Libya and three other... See More
This isn't BBC news special report. Good morning I'm George Stephanopoulos let's -- right the State Department Hillary Clinton about to speak on the death of the US ambassador in Libya and three other Americans. Our US diplomatic post and -- Libya. Was attacked -- heavily armed militants assaulted the compound. And set fire to our buildings. American and Libyan security personnel battled the attackers together. Four Americans were killed. They included Shawn Smith. A foreign service information management officer. And our ambassador to Libya Chris Stevens. We are still making next of kin notification is for the other two individuals. This is an attack that should shock the conscience that people of all face around the world. We condemn in the strongest terms. This senseless. Act of violence. And we send our prayers to the families friends. And colleagues. Of those we lost. All over the world every day. America's diplomats and development experts risk their lives. In the service of our country and our values. Because they believe that the United States must be a force for peace and progress in the world. That these aspirations. Are worth striving and sacrificing for. Alongside our men and women in uniform they represent. The best traditions of -- And generous nation. In the lobby of this building the State Department. The names of those who have fallen in the line of duty are inscribed. In -- Our hearts break over each one. And now because of this tragedy. We have new heroes to honor. And more friends. To -- Chris Stevens fell in love with the Middle East as a young peace corps volunteer teaching English in Morocco. He joined the foreign service learned languages. One friends for America in distant places and made other people's hopes his -- In the early days of the Libyan revolution. I asked Chris to be our. Envoy. To the rebel opposition. He arrived on a cargo ship in the -- of Ben -- -- And began building our relationships. With Libya's revolutionaries. He risked his life to stop -- tyrants. Then gave his life. Trying to help build a better Libya. The world needs more Chris Stevens is. I spoke with his sister and this morning and told her. That he will be remembered as a hero by many nations. Sean Smith. Was an air force veteran. He spent ten years as -- information management officer in the State Department. He was posted at The Hague. And was in Libya on -- brief temporary assignment. He was husband. To his wife Heather with whom I spoke this morning. He was a father to two young children. Samantha and Nathan. They will grow up being proud of the service their father gate to our country. Service that took him from Pretoria. To Baghdad. And finally he's been -- The mission -- that drew Chris and Sean and their colleagues to Libya. It is both noble and necessary. And we and the people of Libya honor their memory by carrying it forward. This is not easy. Today many Americans are asking. Indeed. I asked myself. How could this half. How could this happen in a country. We helped liberate. In a city we help save from destruction. This question reflects just how complicated. And at times. How -- founding. The world can be. But we must be clear -- even in our grief. This was an attack. By a small and savage group. Not the people or government of Libya. Everywhere Chris and his team wins in Libya. In -- country's scarred by war and tyranny they were hailed as friends and partners. And win the attack came yesterday. Libyans stood and fought to defend our post. Some were wounded. Libyans Kerry Chris -- body to the hospital. And they helped rescue and lead other Americans to safety. And last night when I spoke with the president of Libya he strongly condemned the violence and pledged every effort. To protect our people and -- -- response. The friendship between our countries. Born out of shared struggle. Will not be another casualty. Of this attack. A free and stable Libya is still. In America's interest. And security. And we will not turn our back on the off. Nor will we rest until those responsible for these attacks are found and brought to justice. We are working closely with the Libyan authorities to move swiftly and surely. We are also working with partners around the world to safeguard other American embassies. Consulates and citizens. There will be more time later to reflect but today we have work to do. There is no higher priority than protecting our men and women wherever -- they serve. We are working to determine the precise motivations and methods of those who carried out this assault. 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 religion or faith. And as long as there are those who -- take innocent life in the name of god. The world will never know it's true and lasting peace. It is especially difficult. That this happened on September 11. It's an anniversary that means a great deal to all Americans. Every year on that day we are reminded that our work is not yet finished. That the job of putting an end to violent extremism. And building a safe and stable world continues. But September 11. Means even more than that. It is a day on which we remembered thousands of American heroes. The bonds that connect all Americans. Wherever we are on this earth. And the values that see us through every storm. And now it is a day on which we will remember. Sean Chris and their -- May god bless them. And may god bless the thousands of Americans working in every corner of the world who make this country. The greatest force. For peace prosperity. And progress. And a force. That has always stood. For human dignity. The greatest force the world has ever known. And may god continue to bless the United States. Think you. Secretary of state Clinton condemning those attacks on Americans in Libya that she says should shock the conscience of people of faith all around. The world she says the American diplomats were killed Ron noble. And necessary mission want to bring in Martha gratitude comes a State Department national security issues. For us and -- even reporting on this overnight do we have any better idea of what exactly happened there in -- Well I think quit. Secretary Clinton did reveal is that Libyans carried the ambassador to the hospital it is still unclear exactly how he died whether it was smoke inhalation. Whether he was trying to get out in a car with security officers -- that car might have been hit by a mortar. Or something else it is unclear and I cannot get a straight answer from anyone exactly how he died but he was unaccounted for. Four hours George. And there is a -- circulating on the web that is looks very much like the ambassador and he is being carried. By Libyans and apparently. The Libyans did carry him to the hospital the secretary also asking what many are asking how could this happen. Especially on the anniversary of 9/11 would've thought the security would be much -- American embassies. For you sure would have George 9/11 there were security alerts. In this country in other places overseas. Being on guard for something exactly like this there weren't marine guards at this consulate they're never have been -- marine guards. At the embassy in Tripoli but not there there were about a dozen people connect consulate this happened. At night and clearly chaos erupted they did not apparently have any sort of evacuation plan that worked. One of the Americans definitely did died from smoke inhalation that was likely Sean Smith. -- the other two again we don't know how those other two Americans died whether it was on the consulate grounds whether anybody managed to make it off whether they were nearby. But the fact that the Libyans had to carry the ambassador to the hospital tells you something about the security there it sure does -- can -- right stand by will be coming back in just a bit. When President Obama addresses the nation the right now we want to return to regular program. For many -- -- that is Good Morning America. This -- -- special.
This transcript has been automatically generated and may not be 100% accurate.