Two out of the four U.S. Marines shown urinating on Afghan corpses in a viral video have been identified.

The Naval Criminal Investigative Service, which is heading the inquiry into the video, interviewed two of the Marines shown, according to reports.

The investigation began after the video was released and went viral Tuesday.

Initial reports suggest charges are likely to be filed against the two identified Marines, whose names have yet to be released to the public.

The men shown in the video all were a part of a sniper unit from Camp Lejeune, North Carolina, which served in Afghanistan, according to a Marines spokesman. The soldiers have reportedly moved on to other assignments in the military.

Though the names of the soldiers involved have not been released, U.S. Defense Secretary Leon Panetta said the four will be punished, according to reports.

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''This conduct is entirely inappropriate for members of the United States military and does not reflect the standards of values our armed forces are sworn to uphold,'' Panetta said. ''Those found to have engaged in such conduct will be held accountable to the fullest extent.''

The video shows combat-uniformed Marines urinating on three bodies dressed in standard Afghan clothing while making comments and holding state-issued weapons.

''I have seen the footage and I find the behavior depicted in it utterly deplorable,'' Panetta said.

It is unclear what punishment the Marines in question will face.

The video sparked sharp criticism from groups across the globe, including Taliban and Afghan officials.

It is not confirmed whether the bodies shown in the video are dead Taliban or civilians.

''This act by American soldiers is simply inhuman and condemnable in the strongest possible terms,'' Afghanistan president Hamid Karzai said.

Officials are acting swiftly to prevent fallout and damage to the U.S.-Afghan-Taliban peace talks.

It is unclear when the names of the identified soldiers will be released.