A leaked recording of conversation between an Iranian pilot and a control tower prove that Iran immediately knew it had shot down a passenger jet that crashed near Tehran last month, Ukraine’s president has said.

An audio recording obtained by Ukrainian media on Sunday evening purportedly captures a conversation between an Iranian pilot coming in to land at Tehran’s international airport and a control tower there on 8 January, shortly after Ukraine International Airways flight 752 had departed from Tehran.

About 6.12am, according to a transcript, the pilot for the Iranian airline Aseman alerted the control tower that he had seen something suspicious in the sky. “Flares on route, as if from a missile,” he said. “Should anything like this be happening there?”

Asked for clarification, he replies: “That surely is the light from a missile.”

The recording captures several attempts by the control tower to contact the Ukrainian passenger jet, which had been disabled after being struck by two missiles and was falling towards a field outside Tehran with 176 people onboard.

“Ukraine International Airlines 752, do you read?” the control tower repeatedly asks with increasing urgency over more than two minutes. All the passengers and crew onboard the jet were killed.

Iran initially attributed the plane crash to technical difficulties, a conclusion that Iranian spokesmen, military leaders and diplomats publicly defended before the government admitted three days later that its forces had mistakenly shot down the aircraft.

The country had fired a volley of cruise missiles at US forces stationed in Iraq several hours before, in retaliation for the 3 January killing of an Iranian general Qassem Suleimani, and a missile-defence operator had mistaken the plane for a US cruise missile, military leaders said.

They admitted they knew a missile had taken out the plane but attributed the delay in making a public admission to the need to properly investigate the crash to rule out other causes, such as whether foreign hacking may have been involved.

Ukraine’s president, Volodymyr Zelenskiy, who has repeatedly expressed frustration at the way Iran is handling the investigation into the incident, said in a television interview that the audio “proves that the Iranian side knew from the start that our plane had been hit by a missile”.

He said: “[The pilot in the recording] says that ‘it seems to me that a missile is flying’. He says it in both Persian and English, everything is fixed there.”

The chief crash investigator at Iran’s Civil Aviation Organisation appeared to verify the leaked recording on Monday morning, citing the “strange” leak as he announced he would no longer share evidence from the crash with Ukraine.

“The technical investigation team of the Ukrainian airline crash, in a strange move, published the secret audio file of the communications of a pilot of a plane that was flying at the same time as the Ukrainian plane,” Hassan Rezaifar said, according to the semi-official Mehr news agency. “This action by the Ukrainians led to us not sharing any more evidence with them.”

Ukraine has been pressing Iran to turn over to them the black box recording devices recovered from the flight so they can be decoded, which Tehran initially agreed to do before it backtracked without explanation. Ukrainian investigators were to travel to Tehran on Monday to participate in the decoding effort.