Two coalition commandos who were previously believed to have been killed by an Islamic State improvised explosive device were actually killed by friendly fire, a report reveals.

An internal investigation by the British Ministry of Defense (MoD) concludes Delta Force operator Master Sgt. Jonathan Dunbar and Special Air Service (SAS) Sgt. Matt Tonroe were killed by an accidental detonation of coalition explosives.

The two commandos were part of a joint special operations team that was conducting a high-value-target operation in the outskirts of the Syrian city of Manbij. Five others were wounded by the explosion.

A trained sniper, Sergeant Tonroe had been a paratrooper before trying and passing the grueling SAS selection and reinforcement cycle. His death forced the British government to acknowledge the fact British Special Operations Forces (SOF) were operating inside Syria. Previous to that, the British MoD had stated British personnel were confined within the territorial borders of Iraq. Considering the porous nature of the borderline, however, such a “limitation” was not only redundant but also inapplicable. Its sole purpose was to cushion the British government from potential political fallout for having deployed troops inside Syria.