A U.S. military official Tuesday said an Iranian drone flew about 100 feet from an American fighter jet in the Persian Gulf in a potentially dangerous incident.

The Navy said the incident involved an F/A-18E Super Hornet that was preparing to land in international airspace on the aircraft carrier USS Nimitz in the central Gulf.

“The F/A-18E maneuvered to avoid collision with the QOM-1 [Iranian drone] resulting in a lateral separation of approximately 200 feet and a vertical separation of approximately 100 feet,” spokesperson Lt. Chloe J. Morgan said in a statement to CNBC.

According to the statement, the U.S. military made “repeated calls to stay clear of the fixed-wing flight operations in the vicinity of USS Nimitz,” but the Iranian drone still “executed unsafe and unprofessional altitude changes” close to the American F/A/-18E that was “in a holding pattern preparing to on the aircraft carrier.”

The Navy said the action by the Iranian QOM-1 drone “created a collision hazard and is not in keeping with international maritime customs and laws.”

The Navy official also indicated this incident marked “the 13th unsafe and/or unprofessional interaction between U.S. and Iranian maritime forces” so far this year.