KYIV, Ukraine — Russia is working to fabricate evidence and frame Ukraine for an attack that killed dozens of Ukrainian prisoners of war, U.S. and Ukrainian officials told NBC News Thursday.

Describing recently declassified intelligence, a U.S. official said the United States expects Russian officials to falsify intelligence about the July 29 attack on the prison camp in Olenivka, which Kremlin-backed separatists in Ukraine's eastern Donetsk region said killed 53 and injured 75.

Ahead of likely future visits by international investigators and journalists to the attack site, the official said, “We have reason to believe that Russia would go so far as to make it appear that Ukrainian HIMARS were to blame.” HIMARS refers to High Mobility Artillery Rocket Systems, advanced medium-range rocket launchers, which the U.S. recently provided to Ukraine.

Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, said Ukraine had exchanged intelligence information with other nations corroborating Russian plans to frame Ukraine for the attack.

“There was no artillery strike from any area. It was an internal detonation inside one building where our prisoners of war were moved,” Podolyak told NBC News in an interview at the presidential office in Kyiv. “Russia made this terrible cover-up to hide its war crimes.”

Russia’s military has asserted that Ukraine launched the strike on its own prisoners using U.S.-provided weapons, a claim Ukraine has vehemently disputed.

A pre-trial detention center damaged in a rocket attack in Olenivka (Ria Novosti / Sputnik via AP)
© Ria NovostiA pre-trial detention center damaged in a rocket attack in Olenivka (Ria Novosti / Sputnik via AP)

“Ukraine killed its own prisoners and many wounded,” Kremlin spokesman Dmitry Peksov said Thursday. “There is a lot of evidence. There is nothing to hide.”

Ukrainian officials with knowledge of intelligence findings about the attack said that organized Russian efforts to frame Ukraine for the attack had started well before the prisoners were killed.

On July 28, the day before the strike, Russian channels on the messaging service Telegram known to spread Kremlin propaganda were predicting that Ukraine would attack with HIMARS, Ukrainian officials said, describing it as a pre-emptive attempt to prepare the Russian population to accept Russia’s narrative that Ukraine was behind the attack.

Before the site exploded, prisoners who had been held elsewhere were moved for no apparent reason to the specific industrial site where they were killed, according to Ukrainian officials who cited Russian sources, intelligence channels and information from the prisoners themselves, although they declined to elaborate on how they acquired that information.

Satellite imagery reviewed by Ukraine’s government also showed that graves were dug at the Olenivka site beforehand, Ukrainian officials said.

They added that there was some evidence suggesting that some of the POWs were already dead prior to the strike, such as the absence of shrapnel wounds or burn injuries on the bodies that would be expected if they had died from a military strike.

The officials weren’t authorized to be identified by name and spoke on the condition of anonymity.

Russia’s defense ministry has claimed that Ukraine intentionally targeted its own prisoners of war to deter its soldiers from surrendering, arguing that Ukrainian troops know that Russia treats prisoners of war so well that many of them are now voluntarily giving themselves up.

Ukrainian officials said they believed Russia may have had dual motives: First, to stoke chaos that would lessen Ukrainian morale, and second, to make the Ukrainian military appear incompetent in using the U.S.-made HIMARS and other advanced weapons, in hopes of undermining U.S. support for providing heavy weaponry to Ukraine.

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Although Russia has said it has invited the United Nations and the International Committee of the Red Cross to investigate, the Red Cross said Thursday it still hasn’t been given access to the site.

“We are ready to deploy to Olenivka,” said the Red Cross, whose access to prisoners of war is mandated under the Geneva Convention.

United Nations Secretary-General Antonio Guterres said Thursday that he was appointing a fact-finding mission in response to requests from Russia and Ukraine to investigate the killings at the prison.

Podolyak, the Zelenskyy adviser, also said that the Ukrainian leader was seeking direct talks with Chinese President Xi Jinping, in the hope of persuading Beijing to withhold support and supplies to its ally in Moscow. He said Zelenskyy has been seeking a conversation with Xi since the war began.

“China is still participating in this war, not directly but indirectly,” Podolyak said. “President Zelenskyy is looking for any opportunity to reduce the resource capabilities of the Russian Federation.” 

Josh Lederman reported from Kyiv, and Peter Alexander from Washington.