A drone operated by the United Arab Emirates (UAE) killed 26 unarmed cadets at a military academy in Libya's capital Tripoli in January, a new BBC special report has revealed.
At the time of the attack, on 4 January, Tripoli was under siege by the self-styled Libyan National Army (LNA), the report explained.
The BBC says the UAE has denied responsibility for the attack and suggested the cadets had been killed by local shelling. But evidence indicates the cadets were hit by a Chinese Blue Arrow 7 missile.
This was fired by a drone called the Wing Loong II, a BBC investigation found.
At the time of the strike, Wing Loong II drones were only operating from one Libyan air base – Al-Khadim – and the UAE supplied and operated the drones that were stationed there.
One of the survivors, 20 year-old Abdul Moeen told the BBC that he was inside the academy when the strike hit. "It was indescribable," he said.
We were witnessing our colleagues dying, breathing their last breath, and we couldn't do anything… There were guys whose torsos were separated from their bodies. It was an awful crime, a crime that has nothing to do with humanity.
The news organisation also found new evidence that Egypt is allowing the UAE to use Egyptian military air bases close to the Libyan border.
According to report, the Wing Loong II drones stationed in Libya appear to have been moved over the border into Egypt, to an air base near Siwa in the western Egyptian desert.
The UAE has previously denied military involvement in Libya and says it supports the UN's peace efforts. It did not respond to the BBC's request for comment.
Both the UAE and Egypt have been backing renegade General Khalifa Haftar's LNA against the internationally recognised Government of National Accord (GNA), which is backed by Turkey.