Screenshot of video which allegedly shows U.S. Marines urinating on dead Taliban.

"I have seen the footage, and I find the behavior depicted in it utterly deplorable,"Panetta said in a written statement Thursday. "This conduct is entirely inappropriate for members of the United States military and does not reflect the standards or values our armed forces are sworn to uphold. Those found to have engaged in such conduct will be held accountable to the fullest extent."

Officials from the Pentagon have not authenticated the video, which shows four Marines urinating on three bodies of Taliban fighters.

Afghan President Hamid Karzai "condemned the video, describing the men's actions as 'inhuman' and calling for an investigation," according to Reuters.

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