A U.S. Navy vessel was forced to fire warning shots at an armed Iranian patrol boat in the Persian Gulf on Tuesday, according to Defense officials.

At approximately 3:00AM local time, the Iranian boat, believed to be a part of Iran’s Revolutionary Guard, set course to intercept the USS Thunderbolt, a Cyclone class patrol ship currently conducting exercises in the region along with a number of other American vessels, including the Ticonderoga-class guided missile cruiser USS Vella Gulf.  The Iranian boat came to within 150 yards of the Thunderbolt, despite a number of warnings issued via radio, firing flares, and blowing the vessel’s whistle as a warning.  The type of boat employed by the Iranians has not yet been disclosed.

Blowing the ship’s whistle in five short blasts is considered an internationally recognized communications signal for danger.

At that point, the decision was made to fire warning shots into the water ahead of the Iranian boat.

“The IRGCN boat was coming in at a high rate of speed. It did not respond to any signals, they did not respond to any bridge-to-bridge calls, they felt there was no choice except to fire the warning shots,” the official told the AFP news agency.

The warning shots successfully dissuaded the Iranian boat from coming any closer, though it did loiter in the area for hours after the interaction, as observed by U.S. Navy and Coast Guard vessels in the vicinity.

Cyclone class patrol ships like the 179-foot long USS Thunderbolt are equipped with two 25mm Mk-38 machine guns, four .50-caliber machine guns, two MK 19 automatic grenade launchers, and two M-60 machine guns.  They are capable of reaching speeds in excess of 35 knots (40 miles per hour) and are primarily tasked with littoral operations like coastal patrol and interdiction surveillance.  They are often used to protect our nations’ coastlines, but have also been forward deployed to regions like the Persian Gulf in support of the Global War on Terror.

In the highly unlikely event the Thunderbolt had found itself outgunned by the Iranian vessel, the nearby Vella Gulf, a guided-missile cruiser which carries a varied compliment of vertical launch missiles, Tomahawk cruise missiles, six MK 46 torpedoes, two MK 45 5-inch/54 caliber lightweight guns, and two Phalanx close-in-weapons systems, would present a significantly larger threat to any Iranian vessels in the area.

This encounter is hardly the first incident between the Iranian Revolutionary Guard and the U.S. Navy, who have to travel through the narrow Strait of Hormuz en route to operational regions within the Persian Gulf.  Iranian fast attack boats frequent the waters of the strait, and have challenged the U.S. Navy a number of times before.

In June, an Iranian vessel trained its targeting laser on a U.S. Navy helicopter accompanying a formation of ships transiting the international waters of the strait, prompting American Defense officials to lodge a complaint about their “unsafe and unprofessional” behavior.  In April, an Iranian Islamic Revolutionary Guard Corps ship with its weapons systems manned came to within 1,000 yards of the American destroyer, USS Mahan, and three months earlier, that same American ship was forced to fire warning shots at five Iranian vessels that were rapidly approaching it.

According to US Navy Capt. Jeff Davis, spokesman for the Department of Defense, there were at least 35 separate incidents of unsafe or unprofessional behavior attributed to the Iranians in 2016 alone.

Image courtesy of the U.S. Navy