Afghan President Hamid Karzai called on the U.S. government to investigate the video and hand down the harshest punishment possible.

"The government of Afghanistan is deeply disturbed by a video that shows American soldiers desecrating dead bodies of three Afghans," according to a statement released by the presidential palace on behalf of Karzai.

"This act by American soldiers is simply inhuman and condemnable in the strongest possible terms."

A Taliban spokesman called the video "barbaric."

"And no religion that follows a holy text would accept such conduct. This inhuman act reveals their real face to the world," Taliban spokesman Qari Yousuf Ahmadi said via text message Thursday.

The U.S. Embassy in Kabul said in a statement Thursday it "strongly condemns" the actions in the video.

"Such actions are reprehensible, dishonor the sacrifices of our military and the American people and violate the core values of both our societies," the embassy said.

"Islam gives values and respect to every human being," regardless of which religion the individual follows, said Islamic scholar Mawlawi Enayatullah Baligh. "The value and respect is the same for an alive person and a dead body. Even the body of your enemy in the battleground is respectable in Islam."

The video surfaces at a critical time for relations among the United States, the Afghan government and the Taliban.

Last year, the United States outlined its plan to withdraw its troops from Afghanistan, beginning by pulling out 33,000 "surge" troops who had been deployed to help quell the violence by the end of 2012. The remaining 68,000 troops would be withdrawn by the end of 2014.

Meanwhile, the Taliban tentatively agreed in recent weeks to open an office in Qatar's capital city of Doha, a decision widely seen as an overture aimed at establishing an outside forum for political talks with NATO-led forces and the current Afghan administration, among others.

A senior Marine Corps official who has examined the video said Wednesday that the Marines are carrying 30-caliber sniper rifles and wearing helmets issued to members of Marine 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 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. "We will not speculate on the details but will take all necessary actions to determine the facts."

"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 released Wednesday, 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 Panetta.

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