A US Navy vessel fired three warning shots at a group of Iranian ships that approached the destroyer at high speed in the Strait of Hormuz, Reuters reported.
US defense officials said the USS Mahan had called on the four Iranian Revolutionary Guard Corps ships to slow down, but they continued to approach at high speed.
In response, the American destroyer fired flares and a helicopter dropped a “smoke float” signaling device, according to Reuters.
The Iranian ships had come within 800 meters (half a mile) of the USS Mahan, which was escorting two other ships in the Strait of Hormuz.
Iran has previously harassed US Navy ships in the Persian Gulf and around the Strait of Hormuz, with the most notable case being Iran’s capture of 10 US Navy sailors last January who had drifted into Iranian waters after experiencing mechanical problems.
The Strait of Hormuz is a narrow waterway connecting the Persian Gulf to the Indian Sea through which a fifth of the world’s oil supply passes.
Iran has previously threatened to close off the strait in the past over tensions with the US, a move that would lead to turmoil in global oil markets.
Agencies contributed to this report.