LONDON 

The UK and Norway on Thursday announced a landmark defense agreement under which their navies will operate a combined fleet to track Russian submarines and protect critical undersea infrastructure in the North Atlantic.

The move comes as Norwegian Prime Minister Jonas Gahr Store is visiting the UK.

The Lunna House Agreement, described as the first of its kind, will see the Royal Navy and Royal Norwegian Navy work as an integrated force using an interchangeable fleet of British-built Type 26 anti-submarine frigates, according to a statement by the British government.

The joint fleet will include eight UK vessels and at least five Norwegian ships, supported by autonomous systems, it said.

The deal follows what the UK government says is a 30% rise in Russian naval activity threatening UK waters over the past two years.

“At this time of profound global instability, as more Russian ships are being detected in our waters, we must work with international partners to protect our national security. This historic agreement with Norway strengthens our ability to protect our borders and the critical infrastructure our nations depend on.

“Through joint navy cooperation in the North Atlantic, we’re boosting security, supporting thousands of UK jobs, and showcasing Britain’s world-class shipbuilding on the global stage,” the statement said.

The UK Defense Secretary John Healey and Norwegian Defense Minister Tore O. Sandvik are expected to sign the agreement at 10 Downing Street before travelling to Portsmouth to meet the UK-Norway Maritime Capability Coalition, which supports Ukraine’s naval training and equipment needs.

Under the new arrangement, the joint frigate fleet will patrol the strategically important Greenland-Iceland-UK gap, safeguarding underwater cables and pipelines carrying communications, electricity, and gas.

Both navies will share maintenance, technology, and equipment to ensure rapid deployment.

The agreement also includes UK participation in Norway’s program to develop motherships for uncrewed mine-hunting and undersea warfare systems, year-round Royal Marines training in Norway, adoption of Norwegian naval strike missiles by the Royal Navy, deeper collaboration on Sting Ray torpedoes, joint wargaming, and a joint effort to lead NATO’s use of autonomous systems in the high north.