As Russia is accused of hybrid warfare against the West, vital undersea cables show their vulnerability

London — Over 95% percent of the world’s internet traffic and voice and communication data flows through a vast network of fiber optic cables laid across the floors of oceans and seas. The cables are faster, more reliable and cheaper data carriers than alternatives such as satellites, and they have become indispensable to modern life. 

They are the veins and arteries that link our deeply interconnected world, transmitting data for everything from sensitive government and military information and text messages between friends, to trillions of dollars worth of financial transactions every day, underpinning the global economy. 

But our reliance on these undersea cables is a vulnerability, and one that rogue actors have allegedly already tried to exploit, including some adversaries of the United States. 

Russia has been accused recently by America’s NATO allies of increasing “hybrid warfare” against Europe, and analysts say it has shown a clear interest in targeting things like undersea infrastructure.

“That’s quite explicitly a part of Russian thinking regarding modern warfare,” said Sidharth Kaushal, a senior research fellow at the Royal United Services Institute, a British military think tank, in an interview with CBS News earlier this year. 

He said that sabotaging “critical nodes on which society functions… [has been] illustrated in real time in the last few years.”

Since President Vladimir Putin ordered the full-scale invasion of Ukraine in February 2022, Russia has regularly conducted military strikes against Ukrainian energy and transport facilities. But beyond the battlefield, Russia has also been accused of targeting the infrastructure — including undersea cables — that’s vital to other countries, including many of the United States’ NATO allies.

“The sabotage events, they are a new phenomenon,” Gabrielius Landsbergis, the former foreign minister of Lithuania, told CBS News. “They are directly associated with this later stage of Russia’s militarization and aggressive action — not just against Ukraine, but also against the West.”

Russia has denied allegations of interfering with undersea cables and called accusations it has carried out acts of sabotage in Europe “Russophobia.”

What is happening in the Baltic Sea?

The Baltic Sea is a nearly enclosed body of water surrounded by eight NATO countries and Russia.

Relatively few undersea cables connect some of the Baltic NATO members, such as Lithuania, to the rest of Europe and the wider world.

“Baltic states are, you know, not entirely an island, but pretty much so,” Landsbergis told CBS News. “That means that for us [Baltic states] to connect to the Western infrastructure, it’s a rather difficult task. So most of our connections, a big part of our connections, go through the Baltic Sea.”

The Baltic Sea is relatively shallow, meaning ships only need to drag their anchors along the bottom to cause potentially serious damage to cables. That increases the possibility of accidental damage, but also lends plausible deniability to malign actors who would like to carry out sabotage operations there.

And Russia’s “shadow fleet” of vessels, with hazy registration and insurance documentation that allows it to continue transporting oil and other energy products around the world despite Western sanctions imposed over its full-scale invasion of Ukraine, has increased its plausible deniability.

When Finland and Sweden joined NATO, many in the West hoped the Baltic Sea would effectively become a “NATO lake.” Over the last few years, there have been several incidents of alleged Russian sabotage of underwater cables in the sea.

“It is clearly a spike,” Landsbergis told CBS News. “We have never seen almost any incidents during the last, I don’t know, 20 years, and suddenly after [Russia’s full-scale invasion of Ukraine] started, they’re basically recurring every month.”

Targeting the “anthropogenic shell of modern society”

RUSI’s Kaushal said the apparent sabotage operations in the Baltic are an example of the hybrid warfare tactics being increasingly adopted by U.S. adversaries.

“Ever since the 90’s and early 2000’s, the Russians have talked about how the so-called anthropogenic shell of modern society — basically the fragile infrastructure on which it depends — is its Achilles heel,” he told CBS News earlier this year. “Attacks on undersea cables are one major part of that, along with missile attacks (like on infrastructure in Ukraine) and cyberattacks.”

Landsbergis told CBS News that he believes Russia’s objective in disrupting undersea cables is to intimidate local populations, as well as to “test the reactions — you know, how do politicians react? How do militaries react? Whether there is a response or not.”

With the Trump administration pushing hard for its European NATO allies to rely less on the U.S. for their security, “it’s not the question about how we see NATO, but it’s the question how Putin sees NATO,” Landsbergis told CBS News. 

He said without a firm, unified response to the sabotage, Putin could determine “NATO is not the alliance that it has been before Trump,” and that could lead the Russian autocrat to “say, OK, maybe this is the time that I intend to test it.”

What is NATO doing about it?

At the start of this year, NATO launched “Baltic Sentry,” a new operation “to strengthen the protection of critical infrastructure.”

“By working together with all Allies, we will do what it takes to ensure the safety and security not only of our critical infrastructure but of all that we hold dear,” NATO Secretary General Mark Rutte said in a statement announcing Baltic Sentry in January.

The operation involves maritime patrols, aircraft and naval drones, as well as national surveillance assets, according to NATO. The Alliance said it would also work with industry to improve the resilience of undersea cables.

Sweden, another country that shares a Baltic coastline with Russia, broke with its centuries-old policy of military non-alignment and became NATO’s newest member last year, in direct response to Russia’s 2022 invasion of Ukraine.

It staged military exercises earlier this month to practice countering covert espionage and sabotage missions carried out by adversaries in the Baltic Sea.

“We’re not at peace, but not at war,” Swedish submarine flotilla Commander Paula Wallenburg told CBS News during the exercise.

Wallenburg said the current circumstances look “pretty close to” those seen during the Cold War, when the nuclear-armed U.S. and then-Soviet Union tested each other’s resolve in a face off that never quite turned into a full-scale military conflict. 

“It’s a very serious situation when it comes to security here in this area,” she said.

Below is a look at some recent incidents in the Baltic Sea in which Russia-linked vessels have been alleged to have been involved in damaging, or seen loitering around, undersea cables.

Case study: Eagle S

On Christmas Day 2024, an electricity cable and four telecommunications cables linking Finland and Estonia suffered unplanned outages, reducing the two countries’ interconnectivity. Finland’s National Bureau of Investigation later discovered a 60-mile drag mark near the Estlink 2 cable. 

The Eagle S, a crude oil tanker sailing under the flag of the Cook Islands and officially registered to a UAE company, left Russia’s Baltic port of Ust-Luga on the morning of the outages, with its destination listed as Turkey, according to ship tracking data from MarineTraffic.

The ship sailed over one of the Estlink submarine cables in the Gulf of Finland around the time a power failure was reported by the country’s electric grid operators.

The ship’s anchor was later discovered near the point where the drag mark ended. 

Finnish border guards detained the ship and its crew, led by a Georgian national.

The Eagle S was released to international waters in March, but Finland pursued criminal charges against the crew. The case was dismissed in October, when the court ruled prosecutors had failed to prove intent, but prosecutors said they would appeal.

Case study: Two Russian trawlers tracked in area when Svalbard cable cut

In February 2022, Norwegian police told local media they believed “human impact” was to blame for damage to one of a pair of undersea telecommunications cables connecting the country’s mainland with its northern archipelago of Svalbard a month earlier. 

Space Norway, which operates the Svalbard Undersea Cable System, told CBS News the two cables — which were laid as a redundant pair in the event one suffered damage — are the world’s northernmost subsea cable systems.

Space Norway said it detected an outage in the Greenland Sea on Jan, 7.

The damage occurred in an area where the cables descend steeply from a depth of 980 feet to nearly 9,000 feet, the operator told CBS News.

Generally, the cables are buried approximately six feet deep, although there may be variations due to the nature of the seabed, the state-owned company explained, while declining to go into detail about the seabed conditions where the damaged cables were buried.

There was never a loss of service for users in Svalbard, a Space Norway spokesperson said, and the investigation into the cut was eventually closed due to a lack of evidence.

But a report from Norway’s public broadcaster NRK and open-source information showed Russian fishing trawlers made more than a dozen passes over the area before the damage occurred.

Other evidence of “hybrid warfare”

This week, Poland’s top diplomat accused Russia of carrying out an “act of state terror” by blowing up a railway line over the weekend.

“It was an act of not only subversion, as happened before, but an act of state terror as its clear intention was to cause human casualties,” Polish foreign minister Radek Sikorski said.

Poland’s Prime Minister Donald Tusk said two Ukrainian citizens believed to have been working with Russia’s secret services were suspected of carrying out the attack, which he called an “unprecedented act of sabotage.”

The explosion took place on a rail line linking the Polish capital, Warsaw, to Ukraine, and Polish officials said it was used to transport aid to Ukraine.

Russia dismissed allegations that it was involved in the explosion, calling them “Russophobia.”

“The latest sabotage in Poland that could have become a mass casualty event brings even more heightened dimension to the debate,” Landsbergis told CBS News on Thursday.

“Imagine if there would be 100 casualties — would we be still talking about hybrid? Or we would drop the hybrid and just call it war and ask for Article 5?” Landsbergis said, referring to the mutual-defense agreement among NATO members. “The question points to a fact that Russians are pushing the escalation lines even further, forcing us to ask ourselves: Aren’t we at war already?”

The incident came amid a spate of airspace violations, including some near airports and military bases, in Western European nations, usually involving unidentified drones, but also, in at least two instances, Russian warplanes.