Ukraine investigating whether its soldiers committed war crime amid international concern over video

Following the emergence of video suggesting Ukrainian fighters may have committed a war crime by firing on nearly a dozen surrendering Russian soldiers at close range, the country’s prosecutor general on Tuesday announced an investigation into the incident -- although Kyiv has maintained its troops were responding to an attempted ambush.

The Kremlin, meanwhile, claims the brief video clips, which were circulated widely online, show the troops carrying out an execution and is calling for an international investigation.

Ukraine's announcement comes after the U.S. State Department's top war crimes adviser said Monday that U.S. officials were aware of the footage, and underscored that both Moscow and Kyiv are bound to follow the same international law on the battlefield.

"We're obviously tracking that quite closely," Ambassador-at-Large for Global Criminal Justice Beth Van Schaack said of the incident, which took place earlier this month in the Luhansk region of Ukraine.

"It's really important to emphasize that the laws of war apply to all parties equally, both the aggressor state and the defender state," she continued. "But when it comes to the war in Ukraine, that's really where the equivalency ends. When we're looking at the sheer scale of criminality exhibited by Russian forces, it's enormous compared to the allegations that we have seen against Ukrainian forces."

That assessment is supported by multiple international efforts to document war crimes and other atrocities committed in the course of the conflict. The United Nations Under-Secretary-General for Political and Peacebuilding Affairs Rosemary A. DiCarlo reported in September that the body's independent commission was "struck by the large number of executions and other violations carried out by Russian forces" while investigators documented only two incidents of Ukrainian fighters mistreated Russian soldiers.

Van Schaack said how each country's government handles allegations against its service members is also vastly different.

"Russia inevitably responds with propaganda, denial, myths and disinformation -- whereas Ukrainian authorities have generally acknowledged abuses and have denounced, and have pledged to investigate them," she said. "And so we would urge Ukraine to continue to abide by international obligations in this conflict. And we continue to reiterate the importance that all parties to the conflict must abide by international law or face the consequences."

Though the videos, which have been verified by the New York Times, depict a slice of the war's brutal reality, the circumstances surrounding the incident are unclear. The Russian soldiers appear to have opened fire while surrendering, but the actual killings or the events leading up to them are not shown, leaving room for the possibility that the Ukrainian fighters could have acted in self-defense.

While investigating potential crimes on the battlefield is a difficult task, Van Schaack spoke to the challenges that lie ahead for the international justice system once a conviction is reached, acknowledging that Russian bad actors could likely find refuge in their country for years to come -- but perhaps not indefinitely.

"If Russian perpetrators remain in Russia, and absent any kind of political transformation there, it will be difficult to move forward," she said. "But what we have seen in prior conflicts is that perpetrators do inevitably travel, particularly as time passes--they want to visit family, they have other reasons to leave."

But Van Schaack also expressed optimism that the justice would one day reach the highest levels of power in the Kremlin, and that even Russia's President Vladimir Putin might be held accountable for atrocities committed during the invasion.

"Superiors can be held liable for the acts of their subordinates," she said, adding that while prosecutors will follow the evidence, investigators were documenting what appeared to be "systemic acts" that transcended rank and file members of Russia's military.

"It's very hard to imagine how many crimes could be committed without responsibility going all the way up the chain of command," Van Schaack said.