Nearly 50 reconnaissance and intelligence focused Marines are being sent to support a NATO mission monitoring the Baltic Sea’s sprawling network of undersea internet cables and natural gas pipelines.

The Marines will join Enhanced Vigilance Activity Baltic Sentry, an operation that brings together Finnish personnel and other NATO forces. Their assignment centers on surveillance, tactical reconnaissance, and feeding collected information into NATO’s shared operational picture.

The roughly four dozen Marines come from the 2nd Reconnaissance Battalion, 2nd Marine Division, and the II Marine Expeditionary Force Information Group. Both units are based at Marine Corps Base Camp Lejeune, North Carolina.

Marine officials said the deployment is tied, at least in part, to the units’ experience with unmanned reconnaissance drones and other tactical intelligence gathering capabilities. Those systems and skills will be used to help monitor the heavily traveled and strategically important Baltic waters.

Chief of Operations of the Finnish Navy Capt. Johan Tillander said the Marines will supplement Finnish and NATO monitoring efforts across the region.

“The experience, skills and systems of the U.S. Marine Corps are perfectly suited for supplementing our situation picture and supporting our monitoring of the Baltic Sea,” Tillander said.

Reconnaissance Marines are widely known as the Marine Corps’ elite light infantry. Their central capabilities, however, include the less visible work of intelligence, surveillance, and reconnaissance, commonly referred to as ISR.

Those capabilities rely on quietly observing activity, collecting information, and passing useful data to commanders. The II Marine Expeditionary Force Information Group is an intelligence analysis unit trained to keep commanders informed about ISR sources, including information collected by reconnaissance units.

Both participating units were already in Europe for training rotations when they were reassigned to the Baltic operation, according to the Marine Corps release. They will operate with the Finnish Coastal Brigade while providing expeditionary surveillance and tactical reconnaissance capabilities.

The Marine Corps said the mission would “operate alongside the Finnish Coastal Brigade to provide advanced expeditionary surveillance and tactical reconnaissance capabilities. The rotation will leverage the unique capabilities of Reconnaissance Marines, including small Unmanned Aerial Systems and littoral sensors, to feed vital data directly into the shared NATO common operational picture.”

Small unmanned aerial systems will give the Marines another means of conducting reconnaissance over the region. Littoral sensors will also contribute information from the coastal environment as the force works alongside Finnish personnel.

The Marines’ surveillance mission comes as the Baltic Sea and the seafloor beneath it have become an increasingly active front in the simmering conflict between Russia and NATO following Russia’s 2022 invasion of Ukraine. The area is crossed by data cables and natural gas pipelines.

In September 2022, an undersea explosion broke the Nord Stream 1 and 2 pipelines connecting Germany and Russia. A Ukrainian intelligence officer went on trial this month in Germany on charges related to the destruction.

The Nord Stream damage was not the final incident involving infrastructure on the Baltic seabed. Since those attacks, more than half a dozen other attempts have been made to disable or cut pipelines or data networks on the sea floor.

That pattern has placed greater attention on the underwater infrastructure running through the Baltic. The Marines will help build the situation picture used by Finnish and NATO personnel to monitor the waters and the activity around those networks.

The assignment combines the reconnaissance battalion’s collection abilities with the Information Group’s analysis role. Together, the Marines will provide surveillance data and tactical intelligence directly to the wider NATO operation while working beside the Finnish Coastal Brigade.