Video posted on social media on Friday appeared to show a helicopter strike and then a major fire at an oil storage facility said to be in Belgorod, Russia. Reports showed that the facility continued to burn until midday on Friday. Dozens of firefighters were dispatched to battle the inferno, and flames reached dozens of metres into the air.
Other videos showed the helicopters, which are used by both Ukraine and Russia, flying in the region.
Russia has accused Ukraine of sending attack helicopters across the border for what would be the first raid on Russian soil since the outbreak of the war if confirmed. Ukraine has not confirmed that it launched the attack, raising questions about whether Russian negligence may be to blame