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An Iranian drone came within 1,000 feet of a U.S. Navy jet Sunday over the Persian Gulf, the 14th "unsafe" and/or "unprofessional" encounter between the U.S. and Iranian militaries in 2017, according to the Pentagon.

The unarmed Iranian QOM-1 drone made several passes near a U.S. Navy plane that was conducting flight operations off the deck of the carrier USS Nimitz. The drone did not respond to communications from the Navy, according to officials. It also didn't not have its navigational lights on, which one military official called "very dangerous."

Related: Iran Has Drone Base Near U.S. Troops in Syria

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On Aug. 8, an unarmed Iranian drone came even closer to a U.S. Navy plane as the American aircraft was about to land on the Nimitz, according to U.S. Naval Forces Central Command.

Airman Fausto Bautista stands a waist catapult watch aboard the aircraft carrier USS Nimitz in the Arabian Gulf on July 26, 2017. Nimitz is deployed to the U.S. 5th Fleet area of operations in support of Operation Inherent Resolve. Mass Communication Specialist 3rd Class Ian Kinkead / U.S. Navy

Despite numerous radio calls, the drone repeatedly changed altitude and came within 100 vertical feet of the F/A-18. The close call forced the aircraft to maneuver to avoid collision.

Related: U.S. Jet Takes Evasive Action After Close Call With Iranian Drone

The drone "created a collision hazard," U.S. Naval Forces Central Command said, adding that the actions were "not in keeping with maritime customs and laws."

Sunday's close call did not force the U.S. jet to take evasive action. Both incidents took place over international waters.

Related: Russian and U.S. Military Aircraft Have Near Weekly Close Calls

Aircraft from the Nimitz are conducting regular sorties for Operation Inherent Resolve in Iraq and Syria.