In his weekly address, President Obama pays tribute to the four Americans killed in Libya this week, saying they "represented the very best of our country."

"Without people like them, America could not sustain the freedoms we enjoy, the security we demand, and the leadership that the entire world counts on," he says.

The president honors those killed in the assault on the U.S. Embassy in Benghazi, memorializing the lives of Glen Doherty, Tyrone Woods, Sean Smith, and Ambassador Chris Stevens. The president vows that the attackers "will find no escape from justice."

"We will never allow anyone to shake the resolve of the United States of America," he says.

Obama underscores that the United States has "profound respect" for people of all faiths and "we reject the denigration of any religion, including Islam."

"Yet there is never any justification for violence," he says. "There is no excuse for attacks on our embassies and consulates. And so long as I am commander-in-chief, the United States will never tolerate efforts to harm our fellow Americans."

The White House has spoken out against the anti-Muslim film sparking protests at U.S. outposts across the Middle East, although it has not apologized for it, citing freedom of speech.

U.S. officials are still investigating whether the deadly assault on the embassy in Libya was a pre-planned attack or tied to broader protests.

"Let us never forget that for every angry mob, there are millions who yearn for the freedom, and dignity, and hope that our flag represents," Obama says. "That is the cause of America, the ideals that took root in our founding; the opportunity that drew so many to our shores; and the awesome progress that we have promoted all across the globe."