US officials believe that Russia is fabricating evidence regarding the attack on a prison in Olenivka with Ukrainian prisoners of war.

According to AP, US intelligence officials have determined that Russia is trying to plant false evidence to blame Ukrainian troops for the July 29 strike on Olenivka, which killed 53 people and injured dozens more.

Russia claims that the Ukrainian military used US-supplied rocket launchers to shell Olenivka. The Ukrainian military denied launching any rocket or artillery strikes on Olenivka.

The official, who was not authorized to comment publicly and spoke anonymously, said the classified intelligence shows the Russians might even plant ammunitions from the HIMARS as evidence that the provided by the US systems were allegedly used in the attack.

Russia is believed to be taking such measures as it expects anticipates investigators and journalists to eventually get access to Olenivka, the official added.

On Wednesday, UN Secretary-General Antonio Guterres announced launching a fact-finding mission into an attack in the front-line Ukrainian town of Olenivka that killed prisoners held by Moscow-backed separatists. He told reporters he doesn't have authority to conduct criminal investigations but does have authority to conduct fact-finding missions.

High Representative of the European Union for Foreign Affairs and Security Policy, Josep Borrell, condemned the murder of dozens of Ukrainian prisoners of war in occupied by Russia Olenivka.