A decommissioned US Navy frigate has been sunk in the North Atlantic during a major joint military exercise involving US and UK naval and air forces.

The former USS Klakring (FFG-42) was used as the target during Atlantic Thunder 2026, a live-fire exercise conducted around the QinetiQ Hebrides range off north-west Scotland. Footage released by US Naval Forces Europe and Africa showed the frigate being struck during the operation.

The sinking was part of a planned SINKEX, a military exercise in which a retired vessel is deliberately attacked with live weapons. Such exercises allow armed forces to test weapons, targeting systems and operational coordination against a realistic maritime target.

According to the UK Defence Journal, the footage showed the US Navy's USS Paul Ignatius, an Arleigh Burke-class destroyer, launching a missile that struck the former USS Klakring.

Other naval vessels and aircraft from the United States and United Kingdom also participated in the wider engagement, although the complete list of platforms involved had not been released at the time of reporting.

The USS Paul Ignatius is an active US Navy destroyer commissioned in 2019 and based at Naval Station Rota in Spain. Its participation highlights the multi-platform nature of the Atlantic Thunder exercise.

The USS Klakring was an Oliver Hazard Perry-class frigate that entered US Navy service in 1983. It was decommissioned in 2013 and subsequently remained in the Philadelphia Naval Inactive Ship Maintenance Facility.

The vessel was towed from the United States in August 2026 ahead of its use in the exercise off Scotland. Earlier planning identified the ship as the target for the Atlantic Thunder 26 sinking exercise.

The exercise had originally been planned for May but was subsequently moved to September. Its objectives included testing surface-warfare kill chains, allied targeting networks and uncrewed systems under realistic conditions.

Atlantic Thunder is a US-UK multi-domain military exercise designed to improve cooperation between allied forces during maritime operations.

The 2026 edition focused on the ability to detect, target and engage surface vessels while connecting different weapons and surveillance platforms into a coordinated operational network.

The SINKEX also provides an opportunity to examine what happens to a real ship after weapons impact, rather than relying solely on computer simulations or smaller practice targets.

The operation does not end when the target sinks.

The former USS Klakring is expected to settle at a depth of roughly 6,000 feet (around 1,800 metres). Uncrewed underwater vehicles are planned to conduct battle-damage assessment and seabed surveys, allowing military personnel to study the condition and location of the wreck following the live-fire engagement.

This makes Atlantic Thunder more than a conventional missile-firing exercise. The operation combines live weapons testing, naval coordination and post-strike underwater assessment.

The latest sinking exercise follows a similar US-UK operation conducted in 2022, when the former USS Boone was sunk off Scotland.

That exercise involved Royal Navy and US Navy ships alongside aircraft, including RAF Typhoons and US Navy P-8 Poseidon maritime patrol aircraft. The 2022 operation demonstrated how multiple platforms could coordinate attacks against a single maritime target.

The 2026 exercise builds on that experience while incorporating newer operational requirements, including networked targeting and uncrewed underwater systems.

The sinking of the USS Klakring therefore represents a significant live-fire demonstration of US-UK maritime interoperability, anti-surface warfare and weapons coordination in the North Atlantic.