Washington(CNN) US officials are increasingly looking at the possibility an attack in Jordan earlier this month that claimed the lives of three American service members was an act of terror.
The service members were headed to a training facility at the Prince Faisal airbase in Al Jafr on November 4 when they were shot. One was killed immediately while the two others died at an Amman hospital.
Sources said surveillance camera footage is being reviewed and FBI investigators are en route for further investigation. An earlier theory was that the gate guards took the Americans for a threat, but a final conclusion has not been reached.
"The three service members were in Jordan on a training mission, and the initial report is that they came under fire as they were entering the facility in vehicles," Pentagon Press Secretary Peter Cook said in a statement. "We are working closely with the government of Jordan to determine exactly what happened."
The US began training Syrian rebels at locations in Jordan and Turkey last year as part of the continuing fight against ISIS in the region.
The pace and success of the training operation has come under scrutiny over the past year or so as ISIS made gains in the region through the end of 2015.