NATO official warns of growing undersea threats, infrastructure vulnerabilities

As NATO seeks to secure critical undersea infrastructure, one of the alliance’s top maritime security officials has admitted that efforts to safeguard pipelines, cables and offshore energy facilities remain a work in progress and that incidents involving sabotage are almost impossible to investigate.

Speaking at the Arctic Frontiers Conference, Captain Niels Markussen, director of NATO’s Maritime Centre for Security of Critical Underwater Infrastructure, acknowledged that NATO’s response capabilities are still being developed, despite the increasing number of incidents involving potential undersea sabotage.

The center, which is expected to be a key player in safeguarding NATO’s seabed assets, was established in the wake of the Nord Stream 2 pipeline explosions—a moment that forced NATO to rethink how it protects undersea infrastructure.

“As I see it, this all started with the Nord Stream 2 incident,” Markussen said. “At that time, we had a Norwegian secretary-general who immediately recognized the importance of our infrastructure. That was when we started developing from there.”

However, despite the urgency, NATO’s security center is still not fully operational.

“First of all, the center is not finished yet. It’s not operational yet. We are building up the center as we speak,” Markussen said.

While the center is already coordinating security efforts among NATO nations, he described its status as “partly operational”, meaning it lacks full surveillance and defensive capabilities.

A growing threat that is nearly impossible to investigate

The frequency of undersea infrastructure damage has increased sharply, raising concerns about both accidental disruptions and potential sabotage.

“We are now in a situation where we see these incidents so frequently that we cannot exclude that it’s something else,” Markussen said.

Determining whether these incidents are the result of deliberate attacks, accidents, or natural causes remains one of NATO’s biggest challenges.

Even when suspicious activity is detected, attributing responsibility is nearly impossible.

“In my world, which is undersea security outside territorial waters, attribution is very, very difficult. Fingerprints, DNA—you’ll never find that down there,” he explained. “Even if we stop a ship, proving that it was engaged in sabotage is extremely complicated.”

One recent case that raised concerns involved a ship that dragged its anchor for 17 hours, damaging a vital undersea communication cable.

“If we had had the resources and the knowledge we have now, we would have known about it much earlier. We would have had 17 hours to act—call the ship, send a helicopter, or intervene in some way,” Markussen said.

Greenland’s undersea cables a concern

Markussen also discussed Greenland as a vulnerable target, particularly due to its reliance on undersea communication cables that connect its scattered coastal settlements.

“The greatest threat in this area is likely the communication cables across the Atlantic,” he said. “They are vulnerable because they are freely accessible on the seabed.”

Greenland’s isolated geography makes it even more susceptible to a communications blackout if key undersea cables were targeted.

“Greenland is a unique society, spread across small settlements along the coast. That means it is easier to cut communication,” he explained.

A targeted attack could severely impact Greenland’s ability to coordinate with Denmark and NATO, raising serious security concerns for the region.

Markussen also acknowledged that NATO has observed increased Russian and Chinese naval activity near Greenland, though he did not specify whether it posed an immediate threat.

“We know that both Chinese and Russian naval activity is increasing around Greenland,” he said.

NATO struggles to respond and must improve

Markussen outlined several areas where NATO must improve to better protect undersea infrastructure. Intelligence-sharing remains one of the most pressing concerns, as NATO needs better coordination between its member states to detect and respond to threats more quickly.

“We need to get into the minds of those responsible, and that is difficult. We probably never will. But we are showing coherence in the alliance, supporting each other, and improving information-sharing,” he said.

Surveillance technology is also being developed to strengthen monitoring efforts. NATO is working on new warning systems, including intelligent cables that detect movement and ship sound profiling to identify suspicious activity before an attack occurs.

“New warning systems, intelligent cables that detect movement, and ship sound profiling are all being developed to help us identify threats before they happen,” Markussen said.

Legal challenges further complicate NATO’s ability to act. Much of the critical undersea infrastructure is located in international waters, where there is little regulation. Markussen pointed out that this makes the area attractive for those who want to operate outside jurisdiction, describing it as a long-term challenge that NATO must address.

“If you go outside territorial waters, in principle, there’s not much regulation. This makes the area attractive for those who want to operate outside jurisdiction,” he said.

NATO’s defensive posture 

Markussen explained that NATO’s response to an undersea attack would not automatically trigger a military confrontation.

“We have de-escalating rules of engagement. That is the nature of our alliance. We are a defensive alliance,” he said.

However, if an attack on undersea infrastructure escalated, NATO would have to reassess its approach.

“If we go up, then we need to add another level. We have the political level to do something. But of course, the nations have rules of engagement, rules for self-defense and so on,” he said.

With the Arctic and North Atlantic becoming a key battleground for hybrid warfare, NATO’s ability to detect, prevent and respond to undersea threats is becoming a top security priority.

“This is not what we planned for. But this is the reality we must now navigate,” Markussen said.