Washington (CNN) -- A number of websites including TMZ and YouTube posted a video Wednesday showing four men dressed in U.S. Marine Corps combat gear urinating on the apparently dead bodies of three men sprawled on the ground in front of them.

One of the men says, "Have a great day, buddy." A voice asks, "You got it on the video?" to which another voice responds, "Yeah." Another jokes, "Golden, like a shower."

It was not clear who shot or posted the 39-second video, who the people pictured in it were, or where it was shot.

A senior Marine Corps official who has examined the video said the Marines are carrying 30-caliber sniper rifles and wearing helmets issued to members of Marine Corps sniper teams. The helmets are designed with a shorter front and sides so that snipers can place rifles and scopes near their faces.

The official, who said an investigating officer was expected to be named shortly, added that the desecration of a body by U.S. troops could be considered a potential war crime.

"We recently became aware of an inappropriate video on a public website that appears to involve members of our military," International Security Assistance Force spokesman Col. Gary Kolb said from Kabul, Afghanistan. "We will not speculate on the details but will take all necessary actions to determine the facts."

He said an investigation was under way but would not comment on the video's authenticity. The faces of the bodies are not identifiable.

"While we have not yet verified the origin or authenticity of this video, the actions portrayed are not consistent with our core values and are not indicative of the character of the Marines in our Corps," said U.S.M.C. Media Officer Kendra Hardesty. "This matter will be fully investigated and those responsible will be held accountable for their actions. We are in the process of verifying what unit these Marines are with right now and as soon as we have more information, we will let you know."

Did Marines urinate on bodies?

"Regardless of the circumstances or who is in the video, this is egregious, disgusting behavior," said Department of Defense spokesman Capt. John Kirby. "It's hideous. It turned my stomach."

In a statement, the Washington-based Council on American-Islamic Relations condemned the video. "If verified as authentic, the video shows behavior that is totally unbecoming of American military personnel and that could ultimately endanger other soldiers and civilians," wrote CAIR National Executive Director Nihad Awad in a letter to Defense Secretary Leon Panetta.

"Any guilty parties must be punished to the full extent allowed by the Uniform Code of Military Justice and by relevant American laws."

CNN's Barbara Starr contributed to this story.