Top general shares new details on how a US destroyer shot out the engine of an Iran blockade runner

• An Iranian-flagged cargo ship tried to bypass the US blockade in the Arabian Sea last weekend.
• To stop the ship, which ignored warnings, a US destroyer fired nine rounds into its engine room.
• The top American general shared new details about the operation on Friday.

A US Navy guided-missile destroyer fired nine "inert" rounds into the engine room of an Iranian-flagged cargo vessel trying to evade the American military blockade in the Arabian Sea last weekend.

Air Force Gen. Dan Caine, chairman of the Joint Chiefs of Staff, shared new details on Friday about the blockade incident, a rare use of force by the Navy against a non-combat vessel.

Since the US launched its blockade of maritime traffic going in or out of Iranian ports earlier this month, 34 ships have turned around at the direction of American forces. However, one vessel did not comply with those orders, Caine told reporters at a briefing.

M/V Touska, an Iranian-flagged cargo vessel, was sailing in the north Arabian Sea on Sunday, heading toward the Iranian port of Bandar Abbas, when it was intercepted by the Navy destroyer USS Spruance.

The Spruance approached the Touska at around 4 a.m. EST (middle of the day locally). The warship's crew issued multiple warnings to the Iranian-flagged vessel, informing the vessel that it was sailing in violation of the blockade and directing it to turn around, Caine said.

The Touska ignored multiple Navy warnings over a six-hour period before the Spruance "executed a series of preplanned, carefully calibrated escalation options, including firing five warning shots," Caine said, adding that the cargo ship still didn't comply. US commanders then "authorized disabling fire" against the cargo ship.

The Spruance warned the Touska's crew to abandon the engine room, and at around 9 a.m. EST (late afternoon in the north Arabian Sea), the US destroyer fired "nine inert rounds" from its 5-inch MK 45 gun into the engine room, disabling the vessel.

The 127 mm Mk 45 deck gun, standard on the Navy's Arleigh Burke-class destroyers, fires a range of ammunition types tailored to different missions, including high-explosive rounds for direct impact, airburst, and area effects, as well as illumination and inert practice rounds.

The large gun's autoloader holds about 20 ready rounds, which can be fired in roughly a minute at maximum rate, with additional ammunition supplied from the ship's larger magazine below deck. The use of inert rounds in an engagement like the one over the weekend between the Spruance and Touska prioritizes control and safety over outright destruction.

The tactic is intended to target the ship's propulsion system to allow boarding while minimizing danger to the crew.

Hours after the Spruance shot out the engine room, US Marines flew by helicopter to the Touska and boarded the ship by rappelling down onto the deck. American forces have the vessel and its crew in custody.

US forces have also boarded two vessels transporting Iranian oil in the Indian Ocean this week.

More than 17 US Navy warships and over 100 aircraft — including fighter jets, helicopters, and surveillance planes — are involved in enforcing the US blockade of Iranian ports, which started on April 13 and stands to reduce oil revenue critical to Tehran's struggling economy.

The blockade is occurring alongside a US operation to clear Iranian mines from the Strait of Hormuz.

US forces destroyed most of Iran's naval mines during Operation Epic Fury, but Tehran likely placed some in or near the Strait during the war, a defense official told Business Insider. A combination of crewed and uncrewed assets is working to clear the strategic waterway.

President Donald Trump said Thursday that he ordered the Navy to destroy any boat, including Iran's fast-attack boats, laying mines in the Strait of Hormuz.

Meanwhile, a third US aircraft carrier strike group entered the area of responsibility for US Central Command, which oversees American forces in the Middle East, on Thursday, bringing additional firepower to the region amid the tenuous ceasefire between Washington and Tehran.