Three US government defense contractors caught in a blast at a Bulgarian military range were testing out arms for purchase as part of the US-led mission to equip Syrian opposition fighters battling Islamic State, a US military source said on Tuesday.
One American contractor was killed and two more were injured when a rocket-propelled grenade malfunctioned at a military range near the central village of Anevo on Saturday. Two Bulgarians were also injured in the explosion.
Bulgarian prosecutors have opened an investigation into the incident but the authorities declined to say what the Americans were doing in Bulgaria, a NATO member.
According to a US military official who was speaking on condition of anonymity, the US contractors were preparing a deal to buy arms for the US-led effort to train moderate opposition fighters to battle Islamic State in Syria.
"These guys were out there prepping (arms) for eventual transfer ... for the Syria T&E (train and equip) effort," the official told Reuters.