The guided-missile destroyer USS Mahan fired three warning shots at four Iranian fast attack boats in the Strait of Hormuz over the weekend, the U.S. Navy said Monday.

The small boats were armed and considered a potential threat to the Mahan, which was escorting the amphibious assault vessel USS Makin Island and the replenishment oiler USNS Walter Diehl. Capt. Jeff Davis, a Pentagon spokesman, said the boats were speeding toward the U.S. destroyer with weapons drawn.