International War Crimes Charge Against US Unlikely After Kunduz Hospital Bombing, Expert Says

— -- Despite claims by Doctors Without Borders that the U.S. bombing of a hospital in Afghanistan was a "war crime," a top legal expert ABC News spoke with said it is unlikely that international charges will be leveled in the incident, which left 22 dead.

However, there is the possibility that those involved in the bombing could be prosecuted by a U.S. military court.

Following the tragedy, officials with Doctors Without Borders, known internationally as Medecins Sans Frontieres or MSF, called the airstrike an "abhorrent and a grave violation of international humanitarian law," and suggested that a "war crime has been committed."

ABC News spoke to a number of leading war crimes experts, including the prosecutor of the International Criminal Tribunal for the former Yugoslavia and former DePaul University law professor M. Cherif Bassiouni, who explained that the motive behind the strike will matter a great deal.

"In order for something to be called a war crime it has to be done intentionally," Bassiouni said. But the concept of a war crime under the Geneva Conventions can also include gross misconduct or gross negligence.

According to the International Committee of the Red Cross’s summary of the Geneva Conventions, which are the treatises widely accepted as the standard for international law, the military's knowledge of the nature of the location is also vital to the war crime determination.

Senior U.S. military officials have told ABC that the military was deliberately targeting Taliban fighters in the air strike, but have not said if they knew they were targeting a hospital.

"Except in cases of recklessness, targeting errors are not war crimes," the ICRC's summary of the Geneva Convention states, adding that it is "crucial for all those launching attacks to take all feasible measures to minimize incidental civilian harm or mistakes, for instance by verifying targets, selecting tactics, timing and ammunition, and giving the civilian population an effective warning, although a violation of that obligation is not a war crime."

MSF officials say the military had to have known this was a hospital because it had repeatedly provided the U.S. military with the hospital's coordinates, including as recently as one week before the attack.

Hospitals in war zones -- like many other civilians institutions including churches, mosques and schools -- are protected under Article 4 of the Geneva Conventions. Yet if an institution like this is considered dual purpose, meaning it is also being used to harbor enemy forces, it loses that protection under international law.

Yet even if it were proven that the Kunduz hospital had lost that right of protection due to infiltration by Taliban, the U.S. military personnel responsible for the attack would have to prove it was a military necessity to strike that hospital, Bassiouni said.

"You are looking at two things," Bassiouni said. "One is military necessity and the second is proportionality. Was that really militarily necessary? Were these people really posing the type of threat to the U.S. forces who were there in order to necessitate attacking a hospital, violating the principle of neutrality of the hospital, with the potential injuries that could come out to all of the civilians there?”

The other possibility is the military could argue it had no idea the hospital was there. But again, according to Bassiouni, this could fall into the category of gross negligence, which is also grounds for prosecution.

There are currently three investigations underway: an internal military investigation headed by U.S. Brigadier Gen. Richard Kim, plus an investigation led by the Afghan government and an investigation by NATO, both of which the U.S. is participating in. MSF has called for a fourth, impartial investigation to be launched by the International Humanitarian Fact-Finding Commission, an international panel designed to help mediate between conflicting parties. According to this commission, the parties would have to consent to such an inquiry by this body.

Bassiouni told ABC that after all the investigations are finished there may be sufficient evidence to prosecute in an international criminal court, but it probably won’t happen.

That’s because if anyone is ultimately held responsible for this mistake, such as the U.S. special operators who were known to be operating in the area, Bassiouni said, that person or persons will be mostly likely be prosecuted only under the United States Uniform Code of Military Justice.

Bassiouni argues that the U.S. is unlikely to turn any of their service members over to an outside body for prosecution even after facing its own military legal system.

There is no precedent during the Afghan or Iraq wars of the U.S. turning any convicted war criminals to international bodies.

For instance, in the case of Army soldier Robert Bales, who was convicted of killing 16 Afghan civilians in 2012, he was sentenced to life in prison under the Uniform Code of Military Justice in the United States and was not sent to Afghanistan or any other international criminal court for further prosecution.