Feb. 3 (UPI) -- A leaked recording between Iranian air traffic control and an Iranian pilot suggests aviation authorities knew immediately that missiles shot down a Ukrainian passenger plane on Jan. 8, killing 176 on board, Ukraine's president said Sunday.
The revelation could cause more tension between the two countries as they continued their investigation of how and why the airliner was shot down.
"The recording, indeed, shows that the Iranian side knew from the start that our plane was shot down by a missile, they were aware of this at the moment of the shooting," President Volodymyr Zelensky said on Ukrainian television.
Iranian officials said Ukrainian officials received a copy of the recording and called its leaking to the media "unprofessional" and said the recording was classified.
In the recording, a pilot from Aseman Airlines told Iranian air traffic control he saw lights ahead that appeared to be a missile shortly after the Ukrainian-bound plane took off in Tehran. Air traffic control then tried to contact the Ukrainian plane but the pilot said shortly afterward he saw a "big flash" in the sky.
Days later, Iranian officials admitted publicly to accidentally shooting down the plane, citing "human error." The incident happened hours after Iran shot missiles at military bases hosting U.S. troops in Iraq.