After allowing the United States to use its air space to bomb Islamic State fighters for six months, the Syrian army appears to have imposed a “red line” by shooting down a U.S. drone over territory of critical importance to Damascus.

The U.S. military has said it lost contact with one of its drones over northwest Syria but has not given the cause of the incident over Latakia province – part of the western region ofSyria where Damascus has been consolidating state control.

Two U.S. officials, speaking to Reuters on condition of anonymity, acknowledged the Predator drone was likely shot down, although the investigation continues. […]