Iraqi Leader Admits Atrocities in ISIS Fight, Promises Justice

— -- Iraqi Prime Minister Haider al-Abadi confirmed Tuesday that atrocities have been committed by government forces battling ISIS, but in a White House meeting with President Obama he also insisted the incidents were not widespread.

"I have to admit that there are some violations -- human rights violations being committed by some criminal parties and outliers, but we have zero tolerance for any violations of human rights," al-Abadi told reporters as he met with Obama in the Oval Office.

The Iraqi leader's unprompted remarks came on the heels of two well-documented revelations: an ABC News six-month investigation in March that revealed dozens of ISIS-like atrocities perpetrated by government security forces and posted across Iraqi social media sites, and the extrajudicial killing of an ISIS prisoner in Tikrit this month witnessed and reported by Reuters correspondents. In both cases, Iraqi officials promised to investigate.

[In an image posted on Instagram, six black-uniformed men who appear to be Iraqi Special Operations Forces from the “Golden Brigades” surround an alleged ISIS suspect who has been dragged with a rope or cable tied to his foot.]

Obama said probing those within the Iraqi Security Forces responsible for such war crimes will "ensure that the government is accountable for the actions of armed forces so that if there are criminal acts or sectarian retributions that are carried out, that ultimately Prime Minister Abadi is able to call those forces to account and to control them."

Abadi said "criminal elements and some individuals" have been brought to justice for isolated incidents -- though the Iraqi government under the former prime minister, Nouri al-Maliki, was strongly criticized by the Obama administration last year for a culture of impunity among Iraqi security forces accused of torturing and executing terror suspects.

The two leaders in their private Oval Office meeting continued discussing the problem of Iraqi Army, Special Forces and other counter-terrorism units mimicking ISIS with atrocities, according to an administration official.

“The issue of rights abuses did come up. The Prime Minister noted that the Government of Iraq is taking steps to address human rights abuses and will hold those responsible for these abuses accountable," the administration official told ABC News.

Abadi is in Washington to request more guns and bullets, even though Congress in December approved a $1.5 billion gift of more than 50,000 light infantry arms and equipment to Baghdad to fight ISIS. There is ample evidence in social media and news photos that countless American weapons such as M4 rifles have ended up in the hands of those committing atrocities, including Shi'a militias.

[A bound and blindfolded detainee appears to be dropped – or possibly hung from the neck according to one analyst -- from what looks like an Iraqi military base guard tower. The image was posted on Instagram.]

In the case of the extrajudicial killing witnessed by Reuters, the newswire’s Baghdad bureau chief, Ned Parker, was forced to leave the country after receiving threats online tied to Shi’a militias. He’s now back in the U.S.

Prior to that, the videos and images uncovered in the ABC News investigation have been circulating within the dark corners of Iraqi social media for months. In some U.S. military and Iraqi circles, the Iraqi units and militias under scrutiny are referred to as the "dirty brigades".

ABC News came upon the first such images last September, when a reporter following personal Instagram accounts of Iraqi counter-terrorism troops spotted a video of a handcuffed prisoner shot in the head by a man in camouflage -- which more than 600 users "liked." The English and Arabic captions by a self-identified member of the Iraqi security forces said, “We have arrested this terrorist yesterday and we killed him after completion of interrogation."

A separate photo posted in September showed the severed head of a long-haired and bearded alleged ISIS fighter lashed to the grill of a U.S.-donated Humvee bearing an Iraqi Army license plate. A second related photo eventually surfaced of what appeared to be an Iraqi Army soldier holding up the same severed head next to the gun truck. Desecration of war dead and extrajudicial killings are violations of the Geneva Conventions.

"You don’t behead someone and place their head on the front of your Humvee. That’s unacceptable -- because it’s a war crime. And it’s an atrocity," retired U.S. Army Special Forces Lt. Col. James Gavrilis told ABC News in the original report.

[A man wearing a uniform with a patch that appears to be from the Emergency Response Brigade steps on two severed heads in a photo posted on Instagram.]

As a senior officer in 5th Special Forces Group in Iraq a decade ago, Gavrilis was deeply involved in counterinsurgency during the U.S. war and creating Iraqi counter-terrorism units from Special Forces and special police teams.

"I think it’s horrible. I think this really shows a failure of our policy for Iraq," Gavrilis said, confirming that the imagery looked authentic and too plentiful online to be faked. "Both sides are committing war crimes," he said. "This is widespread, it’s endemic."

An Iraqi government spokesperson previously said while the dozens of photos could be ISIS propaganda, a full investigation was warranted.

“Yes, of course we will investigate these pictures,” the spokesperson, Gen. Saad Maan, said as he viewed a selection of images provided by ABC News in an interview in Baghdad that aired last month.

"We don't have anything to hide,” the general said. “We don't have anything to be in, let's say, in a black corner."

ABC News' Devin Dwyer and Erin Dooley contributed to this report.