KYIV, Ukraine — More than 24 hours after a military transport plane’s fiery crash into the snowy fields of a Russian border region, there were still more questions than answers in an episode that has already proved deadly and damaging for Ukraine.

The Kremlin accuses Kyiv of shooting the plane down, knowing 65 of its own prisoners of war were on board. Ukraine has so far not directly confirmed nor flatly denied the accusation, while calling for an international investigation.

It remains to be seen exactly who was on board, what brought the plane down, and where this fits in the high-stakes information battle that has seen claim and counterclaim in the nearly two years since Russia’s full-scale invasion.

The incident comes at a particularly crucial moment for Kyiv, which is struggling to retain Western support and attention. With fighting across the war’s front lines largely at a stalemate, focus has shifted to the air, where Ukraine has increasingly dealt blows to Russia’s more powerful air force and taken aim deeper within enemy territory.

Now that growing power may have taken a tragic turn, and the two sides are battling not for control of the skies, but for control of the narrative.

“It could be a terrible accident, it could be something completely different, or it could be a disinformation campaign,” said Neil Melvin, the director of international security studies at the Royal United Services Institute, or RUSI, a London-based think tank. “All of these scenarios, I think, currently are possible until we can get some more information,” he told NBC News.

‘Messing with the lives of Ukrainian captives’

Reliable information is hard to come by at the best of times in this war, in which both sides tightly control its flow. But with the plane downed inside Russia — no stranger to deadly and mysterious incidents involving aircraft — there seemed little hope that the exact circumstances of the crash would be clarified.

On Thursday, Russia said “fragmented human remains” and flight recorders of the downed plane had been found, but it remains unclear how much information Moscow will share, and whether any independent investigators will be allowed to examine the wreckage or the site. It’s also not clear if any bodies have been recovered.

But the Kremlin lost no time in accusing Ukraine of gunning down its own troops.

The Russian Defense Ministry said that Kyiv knew full well that 65 Ukrainian POWs were on board, but shot the plane down anyway to put the blame on Moscow. A leading Russian propagandist even published a list of the names of those allegedly on board, which Ukraine said contained some who had already been swapped.

On Thursday, Kremlin spokesman Dmitry Peskov called for an international probe into what he called the “criminal actions of the Kyiv regime.”

Andrei Kartapolov, head of the defense affairs committee in the lower house of the Russian parliament, also said that Ukraine was given a 15-minute warning about the plane.

NBC News could not verify the circumstances of the crash or who was on board. The White House said Wednesday it was “trying to get more information” about the incident.

Ukrainian President Volodymyr Zelenskyy called for an international investigation so that “all clear facts” could be established.

“It is obvious that the Russians are messing with the lives of Ukrainian captives, the feelings of their relatives, and the emotions of our society,” Zelenskyy said in a video message.

More than a day after the crash, Ukraine had not directly addressed the circumstances of what happened or if the plane carried its captured soldiers. The country’s military intelligence agency confirmed that a prisoner exchange had been scheduled to take place but insisted that Kyiv was not informed about the need to ensure the safety of the airspace in the area at that time, as it said was the case for previous prisoner swaps.

The agency’s spokesperson, Andriy Yusov, told NBC News that there was still “no reliable information” that there were POWs on board the plane. Asked if Ukraine shot it down, Yusov said “there is no such information” and that his country insists on an international probe.

While its government has largely refrained from directly commenting, many in Ukraine expressed skepticism about the Russian account.

Former Ukrainian POW Maksym Kolesnikov, who was sent home in an exchange last February after nearly a year in Russian custody, told NBC News in Kyiv that he had serious doubts about the Kremlin’s claims.

He said that during his swap there were far more Russian soldiers supervising the POWs than the small number said to have flown with and been killed alongside the 65 Ukrainians on Wednesday.

He also pointed to what he said was the immediacy and synchronicity of the Russian reaction, as well as what he said were other red flags from the scant video and photos that have emerged from the site. “So many people died. Where are the bodies?” he asked. “The POWs wear prison uniforms when they are transferred. It’s hard not to notice that in a snowy field.”

Battling in the skies

Kyiv has delighted in weakening the Russian navy’s stranglehold on the Black Sea, but had spent much of the war struggling to counter its dominance in the skies — a weakness that undermined its efforts to advance on the battlefield and left its cities vulnerable to aerial attacks.

But in recent weeks Ukraine appeared determined to change that.

Zelenskyy has warned that his forces “must gain air superiority” as Ukraine’s cities have been pummeled with airstrikes over the winter.

Less than two weeks ago, Ukraine claimed to have shot down a Russian spy plane and airborne command center, in what military analysts said would amount to one of its biggest successes against Russia’s superior air power since the beginning of the war.

It came as Kyiv has been increasingly taking aim at Russian territories itself. Drones continue to fly over the border, hitting strategic targets including military airfields. Belgorod has come under increasing fire, culminating in a late December airstrike on the region’s namesake capital that killed 24 people.

But the shooting down of the plane Wednesday and the questions over the presence of the POWs on board could turn into a serious setback for Kyiv amid growing reservations in the West about continued funding of Ukraine’s military campaign.

After the crash, Ukrainian Air Force commander Mykola Oleshchuk accused the Kremlin of trying to use the incident to “discredit Ukraine in the eyes of the world” and to weaken international support.

Russian lawmakers alleged, without providing evidence, that American or German-supplied air defense missiles were used to shoot down the plane, in a likely attempt by Moscow to make Kyiv’s allies think twice about donating such munitions again.

But Melvin, with RUSI, said Ukraine’s Western backers were likely to accept that these kinds of incidents are very difficult to prevent in such a contested airspace, where communication and intelligence can be far from perfect, targets move fast and people sometimes have to make split-second judgments.

That’s why it’s paramount for Kyiv to be transparent about what happened to ensure international support is not undermined, Melvin said.

“If it was a genuine mistake, do a transparency inquiry and ultimately admit this was a mistake,” he added. “I think in the Western community, there is an understanding that in war, such things do happen.”

Daryna Mayer reported from Kyiv, and Yuliya Talmazan from London.

This article was originally published on NBCNews.com