A short video released by the U.S. Navy shows the encounter.

Three Iranian Revolutionary Guard speedboats had an “unsafe and unprofessional” close encounter with the Cyclone-class patrol ship USS Sirocco and the fast transport USNS Choctaw County while crossing the Strait of Hormuz, a narrow access route in the Persian Gulf, on the 20th, the U.S. Navy’s Fifth Fleet in the Middle East stated.

The U.S. Navy said one of three Iranian Revolutionary Guard speedboats headed head-on toward the USS Sirocco at high speed before changing course. The U.S. Navy said the Navy warship had to fire a warning flare.

Media reports indicate that Iran did not immediately acknowledge the incident in the Strait of Hormuz. One in five of the world’s oil trade is transported through the Strait.

Sources informed that the background of the incident is the high tension in the region as the nuclear deal between Iran and the relevant world powers are about to collapse due to the stalled negotiations.