Drone-Equipped U.S. Marines Now Helping Protect Baltic Sea Submarine Cables

About 40 drone-equipped U.S. Marines have been sent to Finland to join NATO’s Baltic Sentry effort to protect undersea cables in the wake of several instances of suspected sabotage, according to the Finnish Defense Ministry (MoD) and U.S. Marine Corps. That news comes as Swedish Police say they are investigating a potential new cable break running between Gotland and Germany, the latest in a series of such incidents.

While U.S. Marines routinely train with Finnish forces and U.S. Navy P-8 surveillance aircraft have already participated in Baltic Sentry, this marks the first commitment of American troops. Baltic Sentry was stood up last month by 10 NATO nations in the wake of the suspected sabotage in December of undersea power and communications cables between Finland and Estonia.

U.S. Marines with 3rd Battalion, 1st Marine Regiment, 1st Marine Division, launch an RQ-20 Puma during Integrated Training Exercise (ITX) 5-20 at Marine Corps Air Ground Combat Center (MCAGCC), Twentynine Palms, Calif., June 6, 2020. (U.S. Marine Corps photo by Lance Cpl. Shane T. Beaubien) Lance Cpl. Shane Beaubien

The Marines will use hand-launched RQ-20 Puma surveillance drones to “provide additional maritime domain awareness” to Baltic Sentry, according to the Marine Corps. 

The Pumas “are capable of being operated from sea and land, but their employment will be determined by the Finnish and Marine Corps team on the ground,”  Lt. Col. Zach Leuthardt, a spokesman for U.S. Marine Corps Forces Europe, told us.

U.S. Marine Corps Cpl. Daniel Enders, a rifleman with 1st Battalion, 3rd Marines, 3rd Marine Division, launches an RQ-20 Puma during Mission Rehearsal Littoral Exercise 2022 at Combined Arms Training Center, Camp Fuji, Japan, May 11, 2022. (U.S. Marine Corps photo by Lance Cpl. Sydni Jessee) Lance Cpl. Sydni Jessee

The Marine platoon “will help create the recognized maritime picture and monitor critical undersea infrastructure in the Gulf of Finland by identifying and tracking vessel movements together with the Finnish Navy,” the Finnish MoD said in a statement. 

The Recognized Maritime picture “is created based on multiple different sensors and the analysis formed from this data,” the Finnish MoD told us. “The USMC platoon will use capabilities such as UAVs that can supplement the current Recognized Maritime picture. In other words, they are one node in the network that collects movement of the ships in the Baltic Sea. Sensors that USMC uses are not armed and thus there is no need for specific Rules of Engagement.”

“Having the US Marine Corps unit in Finland and as part of NATO’s Baltic Sentry will strengthen the security of Finland and the Baltic Sea region,” Finnish Defense Minister Antti Häkkänen said in a statement. “This cooperation is a continuation of our active international exercises with our Allies.”

The Marines arrived this week and the length of their deployment has not yet been determined, the Finnish MoD told us. They came to Europe “to train as part of Marine Rotational Force Europe and were dynamically re-tasked to support Baltic Sentry,” Leuthardt explained, adding that they are well-suited for this mission.

“The Marine Corps’ ability to be an expeditionary and agile force, with expertise in littoral environments, makes us a logical partner for this type of enhanced vigilance activity,” Leuthardt noted. “This is another milestone in our long-standing collaborative relationship with Finland and NATO. This mission will set conditions for European allies to bolster their NATO contributions and capabilities.”

U.S. Marines undergoing training with Finnish troops. (NATO)

The deployment is mutually beneficial, spokesman Gen. Christopher G. Cavoli, Supreme Allied Commander Europe of NATO (SACEUR), told The War Zone Friday morning. 

“This is a great opportunity for the two countries to work together, and with other Allies, on an important issue for both America and Europe – the protection of critical undersea infrastructure,” Army Col. Martin O’Donnell said. “This is also a great opportunity for the Marines to hone their cold weather skills. The Arctic is a focus of NATO and the U.S. and anytime we partner with a country like Finland, it is a good thing for the Marines, America and the Finns.”

Having Marines deployed on this mission fits into their new doctrine of positioning small units in littoral areas inside an enemy’s weapons engagement zone (WEZ), though that has been largely focused on the Pacific.

“Being forward inside the weapons engagement zone, with allies and partners, reassuring them every day, by walking the real estate with them, that is deterrence,” Marine Corps Lt. Gen. Karsten Heckl told a virtual panel held by the Center for International and Strategic Studies in 2022.

A Marine Javelin team operates from a small inflatable rubber boat during Exercise Castaway 21.1. (USMC)

Highlighting the need for this cooperation, the Swedish Police on Friday announced that they are investigating “a possible cable break in the Baltic Sea … within the Swedish economic zone. The preliminary investigation into suspected sabotage was opened so that the police can have access to the tools needed to clarify what happened and whether it is a new or old damage.”

There are no suspects yet, the police stated, adding that they are “cooperating with the relevant authorities and have no further information to share at this time.”

“We take all reports of possible damage to infrastructure in the Baltic Sea very seriously,” Swedish Prime Minister Ulf Kristersson said Friday on X. “As I said earlier, they must be seen in the context of the serious security situation that exists.”

“We (Allied Maritime Command and SHAPE) are also in touch with Sweden on reports of a new cable break in the Baltic Sea,” SACEUR spokesman O’Donnell told us. “Sweden’s Coast Guard was informed of the purported break yesterday and is investigating.”

There have been several instances of suspected sabotage of undersea cables, with Russia and China as the prime suspects.

According to Finnish authorities, the Russian-linked Eagle S oil tanker severed the Estlink 2 undersea power cable and four telecommunications cables with its anchor in December. The ship, found to be brimming with spy equipment, was seized and authorities are continuing their investigation. You can see that ship after it was seized by Finnish authorities in the following video.

In November, Germany said damage to two communication cables running under the Baltic Sea was most likely the result of sabotage. The two cables in question are both fiber-optic communication cables, running along the Baltic seabed. One runs between the Swedish island of Gotland and Lithuania, and the other between Finland and Germany. Gotland is about 280 miles southwest of where the Estlink 2 cable was severed.

A day later, Denmark confirmed it was monitoring a Chinese cargo vessel at the center of allegations surrounding that damage. The 735-foot-long Yi Peng 3 was identified as operating near the cables when the incidents occurred. The Chinese vessel had departed the Russian port of Ust-Luga, in the Leningrad region, close to the Estonian border, on Nov. 15 and had been scheduled to sail to Port Said, Egypt, where it was originally due to arrive on Dec. 3.

Last month, Swedish Defense Minister Carl-Oskar Bohlin announced that the Norbalt undersea power cable linking Sweden with Lithuania was likely also purposely damaged by the Yi Peng 3 as well.

Officials suspect the Yi Peng 3 of severing at least three cables running underneath the Baltic Sea. (Photo by Mikkel Berg Pedersen / Ritzau Scanpix / AFP) / Denmark)

The deployment of the Marines to Baltic Sentry comes against the backdrop of the ongoing war in Ukraine, which will mark its third anniversary on Monday. It is part of a greater effort by NATO to establish a more ready force in the face of potential Russian aggression.

“…we will have a rigorous exercise program to enhance our readiness,” Cavoli, the SACEUR, said during a NATO press conference last month. “Allied Command Operations has nearly 100 separate exercises planned in 2025.”

At that press conference, Cavoli stressed there would be limited U.S. involvement in Baltic Sentry, a sign that NATO is more than just an American operation.

“There’s not a single U.S contribution to that,” he said at the time. “I think I’m the only U.S. contribution to it, in fact. So this is an alliance that is not a one-trick pony. This is an alliance that is capable of doing things and is rapidly gaining the ability to do more and more.”

This was before the Navy’s P-8s flew surveillance missions and the Marines were sent in. Whether there will be additional U.S. contributions to Baltic Sentry remains to be seen.

“We don’t speculate about future operations, but would reemphasize what NATO leaders have said in that Baltic Sentry is primarily about regional allies helping regional allies,” Arlo Abrahamson, a NATO spokesman, told us.

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