WASHINGTON — The U.S. military on Thursday was investigating a “disgusting” online video purportedly showing Marines urinating on the corpses of Taliban fighters in Afghanistan, a Pentagon spokesman said.

The video shows what appears to be four servicemen, dressed in U.S. military uniform, relieving themselves onto three bloodied bodies on the ground, apparently aware that they are being filmed.

“Have a great day, buddy,” one of them says, giggling.

It is not clear from the video whether the dead Afghans were Taliban insurgents or civilians.

The Pentagon has not yet verified the video, but spokesman John Kirby said: “Regardless of the circumstances or who is in the video, this is… egregious, disgusting behavior, unacceptable for anyone in uniform.”

“It turned my stomach,” he added of the video, which was posted on the Live Leak website.

If authenticated, the images — which conjure up previous abuses committed by U.S. troops during the decade-long war — could spark deep anger and resentment in Afghanistan and the wider Muslim world.

A military official who asked not to be named said the helmet and weapon carried by one of the men seems to indicate the four could be members of an elite sniper team.

The official also said such conduct would be punishable under the U.S. code of military justice.

The Washington-based Council on American-Islamic Relations (CAIR), a prominent US Muslim civil rights and advocacy organization, condemned the alleged desecration of corpses.

“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,” CAIR said in a statement.

“We trust that this disturbing incident will be promptly investigated in a transparent manner and that appropriate actions will be taken based on the results of that investigation,” the statement said.

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

A statement issued by the Pentagon said: “Headquarters Marine Corps has recently been made aware of a video that portrays Marines urinating on what appear to be deceased members of the Taliban.

“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.

“This matter will be fully investigated.”

Some 20,000 Marines are deployed in Afghanistan, mostly in Kandahar and Helmand provinces in the south of the war-ravaged country, the heartland of the hardline Islamist Taliban movement ousted from power in late 2001.

The United States and its NATO allies have some 130,000 troops fighting the Taliban insurgency in Afghanistan.

U.S. and coalition partners plan to hand over security for the whole of the country to Afghan forces by the end of 2014, allowing the withdrawal of combat forces.

In March 2011 the U.S. military apologized after pictures surfaced of U.S. soldiers from a rogue Army unit posing with dead Afghans. Five soldiers from the unit were charged with murder for allegedly shooting civilians for sport.

The German weekly Der Spiegel, which first published the photos, said the Pentagon had tried to prevent their release, fearing a popular backlash against troops in Afghanistan.

In November the ringleader of the “kill team” — which was also charged with taking fingers and teeth as trophies from civilians killed for sport — was found guilty and sentenced to life in prison by a military panel.

That scandal was among the worst faced by the military since the April 2004 revelation of prisoner abuse at the U.S.-run Abu Ghraib prison in Iraq, which became a potent negative symbol of the U.S. occupation.

Eventually, 11 soldiers were convicted in connection to the abuse, and received punishments ranging from an army discharge to 10 years in prison.