Flight 752, a Ukraine International Airlines plane that was struck by two missiles and crashed shortly after taking off from Tehran’s main airport on January 8, was downed due to faulty radar operation, Iran said on Sunday

“A failure occurred due to a human error in following the procedure” for aligning the radar, causing an error in the system, the Iranian Civil Aviation Organization said in a recent report, which refutes Iran’s previous claim that it had misidentified the aircraft because of heightened tensions with the US at the time.

As a result of this first mishap, there began a chain of successive failures in the minutes before the plane was shot down that eventually ended in tragedy, said the CAO.

The report states that despite the incorrect information available to the radar system operator on the aircraft’s trajectory, he could have identified his target as an airliner, but instead the commercial flight was deemed a threat and fired upon.

Tehran’s air defenses had been on high alert at the time the jet was shot down due to fears of US retaliation in response to Iranian strikes on American troops in Iraq hours earlier. The Iranians initially attacked the Americans in response to the killing of Quds Force Commander Qassem Soleimani in a US drone attack near the Baghdad airport.