Russia's Gray Zone War Against NATO

It’s a battlefield so cold that even Marvel’s Captain America might find himself looking around for a space heater, but that doesn’t mean the fight isn’t warming up.

Russian naval vessels have been mapping the seabed throughout the High North and Atlantic to support efforts to target allied subsea fiber optic cables, the UK’s Ministry of Defense revealed last week. Over the past month, the UK and other NATO militaries have tracked loitering vessels from Russia’s Main Directorate of Deep Sea Research, a highly secretive unit within the Russian Armed Forces that reports directly to the president and defense minister. It specializes in subsea surveillance, sabotage, and reconnaissance.

Moscow’s gray-zone operations in the Arctic and Atlantic oceans and surrounding areas are hardly new, but they have intensified since 2014. Russia reopened Soviet-era bases, reinvested in Arctic-capable platforms, and expanded its operational footprint across the region. Russia routinely interferes with GPS across the High North and Baltics, disrupting military communications, civilian aviation, and emergency services. It also conducts military exercises within NATO countries’ Exclusive Economic Zones and has simulated attacks on regional targets, including a 2018 mock attack on a Norwegian radar facility.

Combatting Russian aggression in the Arctic will always be hard. Sub-freezing temperatures, hardened ice sheets, and chilling fog make the region an unforgiving and extremely dangerous operating environment for warfighters. Yet Western countries braved these conditions during the Cold War to counter Soviet aggression. By conducting persistent under-ice submarine patrols and building early warning systems across the region, like the Distant Early Warning Line, allies maintained a credible deterrent in one of the harshest theaters. Nations must now rekindle their Cold War-era resolve by enhancing interoperability and expanding intelligence, surveillance, and reconnaissance (ISR) capabilities at every level — from seabed to outer space.

Already leading the way on these fronts are the UK and Norway. London’s Atlantic Bastion program, announced in December 2025, is a direct response to increased Russian naval activity. The program aims to build an interconnected network of autonomous ships, submarines, and aircraft that integrates into an AI-enabled targeting system to strengthen UK underwater intelligence capabilities. London and Oslo have also signed multiple joint defense agreements, over the past four months, focused on countering Russian subsea threats, protecting underwater infrastructure, and coordinating military operations. 

Washington must now step up. The United States should assume a greater leadership role by similarly expanding military cooperation with regional allies and reinvesting in Arctic-capable platforms. Even without sustaining a large under-ice submarine presence as in the Cold War, the Pentagon must maintain a credible regional presence and modernize subsea ISR capabilities to counter Russia’s growing seabed and deep-sea gray-zone activities.

The U.S. Navy should also push forward with the secretive revamping of the Integrated Undersea Surveillance System (IUSS), the global anti-submarine cable network originally designed to track Soviet submarines. While public details remain limited, deploying high-tech, autonomous deep-sea drones and advanced microphones and sensors — capable of long-duration operations in harsh Arctic waters — would significantly strengthen U.S. ISR capabilities and the protection of critical subsea infrastructure. The Pentagon should also continue to invest in its undersea surveillance partnerships with Norway and the UK in order to enhance intelligence sharing, improve interoperability, and share procurement costs of next-generation subsea ISR technology.

While Russia was expanding its shadow campaign against NATO, Americans were busy watching superheroes, not realizing how Hollywood’s messaging would soon ring true. In 2014, Marvel’s Captain America called upon fellow Americans to help him defeat HYDRA, a fictional terrorist organization with links to the Soviet Union and Russian Federation, stating “the price of freedom is high, it always has been. It’s a price I’m willing to pay. If I’m the only one, then so be it, but I’m willing to bet I’m not.”

The cost of defending against real Russian aggression is high, too. Arctic-capable platforms are not cheap, and the environment is harsh and dangerous. However, right now NATO allies are sounding the alarm and gathering their defenses. Washington should follow its Captain and lead its allies to defeat Russian aggression (once again).

Rear Admiral Mark Montgomery (U.S. Navy, ret.) is a Senior Fellow at the Foundation for Defense of Democracies (FDD). He served for 32 years in the U.S. Navy, during which time his flag officer assignments included deputy director for plans, policy, and strategy (J5) at U.S. European Command. Emmerson Overell is a Project Coordinator at FDD’s Center on Cyber and Technology Innovation where she focuses on threats to U.S. national security in the Arctic, space, and cyberspace.