An unmanned US military drone was shot down off the coast of Yemen by Houthi forces, a defense official told CNN.

The official said the MQ-9 Reaper drone was operating in international airspace and over international waters when it was shot down. US Central Command is investigating the incident, the official said.

The shootdown, which the Iran-backed Houthi militants took responsibility for earlier on Wednesday, comes several weeks after a US Navy warship, the USS Carney, intercepted multiple missiles and drones fired by the Houthis as they were heading north along the Red Sea. The ship shot down four cruise missiles and 15 drones over a period of nine hours, CNN previously reported, and their trajectory left little doubt that the projectiles were headed for Israel.