A dramatic video shows Russian fighter jets "harassing" US drones over Syria as they carry out missions against Islamic State militants, an official has said.
A US Air Force general slammed the incident on Wednesday as "unsafe and unprofessional behaviour" and said it "threaten[s] the safety of both U.S. and Russian forces,"
He called on Russia to stop the "reckless behaviour" in Syria where US still has 900 troops.
