An Iranian drone aircraft came within 200 feet of a U.S. Navy jet in the Persian Gulf on Tuesday, forcing the pilot to take evasive action during an approach to the aircraft carrier USS Nimitz.

U.S. officials characterized the encounter as an “unsafe and unprofessional interaction” in which the Iranian QOM-1 drone ignored “repeated radio calls to stay clear of active fixed-wing flight operations.” It came within 100 feet vertically and 200 feet horizontally of an American F/A-18E Super Hornet.

“The dangerous maneuver by the QOM-1 in the known vicinity of fixed wing flight operations and at coincident altitude with operating aircraft created a collision hazard and is not in keeping with international maritime customs and laws,” said a statement from U.S. Naval Forces Central Command.

A U.S. defense official told the Navy Times that the Iranian drone “had been loitering about 4 nautical miles away from the Nimitz at an altitude of about 7,000 feet” before initiating the encounter.

CNN cites the Navy’s count of 13 dangerous “interactions” between American and Iranian maritime forces in 2017, following 35 incidents in 2016.

One of the 2016 incidents also involved an Iranian drone flying too close to aircraft carriers – in that case, the American USS Harry S Truman and the French carrier Charles de Gaulle. That encounter was greatly overshadowed in the news by Iran’s abduction of ten American sailors on the same day.

U.S. officials said the Iranian drone was capable of carrying weapons but did not appear to be armed. They further pointed out that carrier landings are extremely difficult, and a near-collision with drone aircraft does not make them easier.

The Washington Post quotes retired Marine Corps pilot Amy McGrath describing carrier approaches as “enormously dangerous” even under ideal conditions. “You have to be 100 percent in it, physically and mentally. It requires so much focus,” she said.

McGrath said the safe resolution of Tuesday’s incident was a tribute to the skill and discipline of the pilot and carrier crew.

“In June, the United States downed two Iranian-made drones that the Pentagon said were approaching American-backed troops on the ground in Syria,” notes the New York Times.