DUBAI, United Arab Emirates — A U.S. Navy guided-missile destroyer fired a warning flare toward an Iranian Revolutionary Guard vessel coming near it in the Persian Gulf, an American official said today, the latest tense naval encounter between the two countries.

The incident happened Monday as the vessel attempted to draw closer to the USS Mahan despite the destroyer trying to turn away from it, said Lt. Ian McConnaughey, a spokesman for the Bahrain-based 5th Fleet.

The “Mahan made several attempts to contact the Iranian vessel by bridge-to-bridge radio, issuing warning messages and twice sounding the internationally recognized danger signal of five short blasts with the ship’s whistle, as well as deploying a flare to determine the Iranian vessel’s intentions,” McConnaughey said.

The Iranian vessel came within 1,100 yards of the Mahan during the incident, the lieutenant said, before it turned and sailed away.

The U.S. and Iran routinely have tense encounters in the Persian Gulf and the nearby Strait of Hormuz, through which a third of all oil traded by sea passes.