Ukrainian President Volodymyr Zelensky said in an interview that a leaked audio recording proved that Iran knew it had shot down a Ukrainian airliner almost immediately, despite authorities in Tehran initially denying the allegation.

The recording, revealed on Ukrainian television on Sunday, played the voice of an Iranian airline pilot telling a control tower that he saw “the light of a missile” before Ukrainian International Airways Flight 752 crashed soon after taking off.

“Is this an active area? There’s lights like a missile. Is there anything?” the pilot says.

“Nothing has been reported to us. What’s the light like?” the controller asks. The pilot then states “it’s the light of a missile.”

Zelensky said that the audio “proves that the Iranian side knew from the start that our plane had been hit by a missile.” The disaster, which occurred just hours after Iran launched 15 missiles at U.S. troops stationed in Iraq in retaliation for the assassination of general Qasem Soleimani, killed all 176 passengers aboard.

“He says that ‘it seems to me that a missile is flying’, he says it in both Persian and English, everything is fixed there,” Zelensky stated.

Iranian state media had initially reported that the plane crashed due to “technical issues,” and Ali Abedzadeh, who leads the country’s civil aviation organization, said initially he would not hand over the recovered black boxes to the United States.

Abedzadeh then dismissed allegations the plane was shot down, saying it was “scientifically impossible and such rumors make no sense at all.”

“What is obvious for us, and what we can say with certainty, is that no missile hit the plane,” Abedzadeh said at a press conference. “If [Western governments] are really sure, they should come and show their findings to the world.”

Iran later admitted that it had accidentally shot down the plane due to a “human error.”