A television network in Ukraine published a transcript of a conversation on Sunday in which Iranian authorities appear aware that a missile shot down Ukrainian International Airlines (UIA) Flight 752, proving “Iran knew from the start” and lied about the plane’s demise, President Volodymyr Zelensky said.

Zelensky confirmed the authenticity of the transcript – in which an air traffic control official and the pilot of a plane witnessing the missile attack discuss the explosion that took the UIA flight down – and asserted that Kyiv was aware that Tehran was lying when it claimed “mechanical error” had resulted in a “crash.”

Zelensky’s remarks prompted the Iranian government to declare it would cease all cooperation with Ukraine on the probe into the Ukrainian plane’s explosion.

The partial transcript of the conversation appeared at Ukraine’s 1+1 television network. In it, the pilot of a plane later found to be in a location at the time of the call where he could have reasonably seen UIA Flight 752 explode asks the air traffic control tower what he is looking at, specifically describing it as “a series of lights like … is there a missile, is there something?”

“Dear engineer, it was an explosion. We saw a very big light there, I don’t really know what it was,” the pilot says. In the transcript, the air traffic controller then appears to reach out to the UIA flight but does not receive a response.

The transcript indicates evidence that eyewitnesses believed the flight fell to the ground after exploding, and the explosion appeared to be from a missile. Iranian authorities would be reasonably expected to investigate reports of a missile shooting down an airplane.

“The release of a new record of communications between the Tehran ATC dispatcher and the pilot of the Iranian airline, who saw the missile launch and hit the UIA flight, proves that the Iranian side knew from the very beginning that the plane had been hit by a missile, they’d already known this at the time it was downed,” Zelensky said on Sunday, according to the Ukrainian outlet UNIAN.

Zelensky confirmed Ukrainian intelligence officials procured the audio and that it was authentic. He also insisted that, despite urging Ukrainians not to consider “conspiracy theories” in the immediate aftermath of the plane falling, Kyiv never believed Iran’s claims that the plane fell by accident.

“We knew this couldn’t be the case. I talked about this, maybe not so openly. But, when we came to see parents and relatives of all victims, I said there had been no crew error, that we know this for sure,” Zelensky said, and continued:

We knew then this was a new jet and one of our best crews. We understood that the Iranians – we don’t know who exactly – sought to unlawfully defend themselves in such a way – to push in the media space the information that this had been a technical error. But we already had evidence that this couldn’t be the case.

Zelensky also revealed that Ukrainian investigators faced barriers to investigating the site as soon as they landed in Tehran, illustrating a frustrating landscape for his investigators to do their jobs.

“We were struck that on the first day they had no access anywhere. They couldn’t find many parts of the plane wreckage – there was no cockpit, no seats,” he noted. “And in such cases, by the seats it’s often possible to establish whether there was an explosion, since particles, parts of the device get stuck in soft tissue.”

Zelensky also said that Iran had finally offered to pay compensation to the families of the Ukrainians, mostly crew, who died on the flight, but that it was not enough and he would ask for more.

“They immediately offered US $80,000 to each victim’s family, but we didn’t agree to this. It seems to me this isn’t enough,” Zelesnky noted. “When a victim’s widow says her husband had been feeding the family, while she has no job and still has to get her kid to a university, US $80,000 is not enough. Although, of course, human life can’t be measured by any money, but we’ll be pushing for larger payout.”

He noted that, while Kyiv and Tehran negotiate compensation for victims, he will also insist on an international trial to ensure those responsible for shooting the plane down would appear in court. He did not specify which court he would take the case to; states can be parties at a venue like the International Court of Justice, but the individual responsible for shooting down the plane would have to appear at another venue like the International Criminal Court.

Iran responded to Zelensky’s interview by declaring it would no longer cooperate with Ukraine on investigating the missile attack.

“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,” an Iranian official stated. “This action by the Ukrainians led to us not sharing any more evidence with them.”

UIA Flight 735 exploded and crashed in January, killing all 176 people on board. Iranian officials initially insisted that they had evidence of either human error in flying the plane or mechanical error taking down the engine, but later admitted – after bulldozing the crash site and refusing to hand over the plane’s black boxes – that a Russian Tor missile attack took the plane down shortly after it took off from Tehran’s international airport.

An Iranian soldier is believed to have fired the missile mistaking the plane for an incoming missile. The firing occurred as Iran launched a ballistic missile attack on two Iraqi airbases housing U.S. troops, intended as a response to President Donald Trump ordering an airstrike against Major General Qasem Soleimani. Soleimani, the head of the Islamic Revolutionary Guard Corps (IRGC) Quds Force, organized Iran’s foreign terrorism strategy and was considered among the world’s most prolific terrorists. The IRGC is a U.S.-designated terrorist organization.

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