KYIV, Ukraine (AP) — Ukrainian officials on Sunday launched an investigation into allegations that Russian forces killed surrendering Ukrainian soldiers — a war crime if confirmed — after grainy footage on social media appeared to show two uniformed men being shot at close range after emerging from a dugout.

The video shows the servicemen, one of them with his hands up, walking out at gunpoint and lying down on the ground before a group of Russian troops appears to open fire. It was not immediately possible to verify the video’s authenticity or the circumstances in which it was filmed, and it was unclear when the incident took place.

The Ukrainian General Prosecutor’s office on Sunday launched a criminal investigation, hours after the Ukrainian military’s press office said in an online statement that the footage is genuine.

“The video shows a group in Russian uniforms shooting, at point-blank range, two unarmed servicemen in the uniform of the Armed Forces of Ukraine who were surrendering,” the prosecutor’s office said in a Telegram update on Sunday.

The Russian defence ministry did not immediately respond to an emailed request for comment. As of Sunday evening, there were no public statements from the Russian government or military on the video.

Kyiv, its Western allies and international human rights organisations have repeatedly accused Moscow of breaching international humanitarian law since it launched its full-scale invasion of Ukraine in February 2022. The Kremlin denies these allegations.

The video first appeared Saturday on DeepState, a popular Ukrainian Telegram channel covering the war. The post claimed the footage came from the front lines near Avdiivka, a Ukrainian holdout in the country’s part-occupied east where there has been fierce fighting in recent weeks.

The General Prosecutor’s Office on Sunday said that the alleged killing took place in the Pokrovsk district, which includes Avdiivka and surrounding areas.

“It’s clear from the video that the Ukrainian servicemen are taking the necessary steps that show they are surrendering,” Ukraine’s human rights chief, Dmytro Lubinets, said hours after the footage emerged on Saturday.

In a statement posted to Telegram, Lubinets described the incident as “yet another glaring example of Russia’s violations of international humanitarian law.”

Oleksandr Shtupun, a spokesperson for the Ukrainian military grouping that is fighting near Avdiivka, was cited by Ukrainian media as saying the video was “glaring confirmation” of Moscow’s disrespect for the laws of war.

In March, footage of a man exclaiming “Glory to Ukraine” before being gunned down in a wooded area sparked national outcry in Ukraine, as senior officials alleged that he was an unarmed prisoner of war killed by Russian soldiers.

Last summer, Kyiv and Moscow also traded blame for a shelling attack on a prison in occupied eastern Ukraine that killed dozens of Ukrainian POWs. Both sides claimed the assault on the facility in Olenivka was aimed at covering up atrocities, with Ukrainian officials charging captive soldiers had been tortured and executed there.

The UN’s human rights chief in July rejected Moscow’s claim that a rocket strike had caused the blast.

Also on Sunday, Ukraine’s energy ministry reported that close to 1,000 towns and villages suffered power outages that day, with hundreds of settlements in the west battered by wintry weather and others affected by ongoing fighting.

The Institute for the Study of War, a Washington-based think tank, late on Saturday assessed that military operations have slowed down all along the frontline in Ukraine due to poor weather, with mud bogging down tracked vehicles and making it hard for lighter equipment and infantry to advance.

Even so, Shtupun, of Ukraine’s Tavria military command that oversees the stretch of frontline near Avdiivka, said in a separate statement Sunday that Russian infantry attacks had intensified in the area over the past day. In a Telegram post, he insisted Ukrainian troops were “holding firm” in Avdiivka and another nearby town.

In the southern Ukrainian city of Kherson, at least two people died and seven more were wounded after Russian forces on Sunday shelled a high-rise apartment block and other civilian buildings, the head of the city’s military administration said in a series of Telegram posts.

One of the updates by Roman Mrochko featured a blurred photo of what he said was the body of a deceased civilian, apparently lying on a dirt road or in a yard outside the high-rise. The photo’s authenticity could not be independently verified.

Regional Governor Oleksandr Prokudin separately reported on Sunday that Russian shelling that day damaged two of Kherson’s hospitals. He did not immediately reference any casualties.

Earlier in the day, a 78-year-old civilian died in a village northeast of Kherson after Russian shells slammed into his garage, according to a Telegram update by the regional Ukrainian military administration.