Two undersea internet cables disrupted in the Baltic Sea, prompting warnings of possible ‘hybrid war’

()— Two undersea internet cables have been suddenly disrupted in the Baltic Sea, according to local telecommunications companies, amid fresh warnings about possible Russian interference with global undersea infrastructure.

A communications cable between Lithuania and Sweden was cut Sunday morning around 10:00 a.m. local time, a spokesperson for telecommunications company Telia Lithuania confirmed to .

The company’s monitoring systems were able to detect that an outage occurred due to traffic disruption, and that the cause was likely physical damage to the cable itself, Telia Lithuania spokesperson Audrius Stasiulaitis told . “We can confirm that the interruption to internet traffic was not caused by equipment failure, but rather by physical damage to the fiber optic cable.”

Another cable linking Finland and Germany was also altered, according to Cinia, the Finnish state company that operates the link. The C-Lion cable – the only direct connection of its kind between Finland and Central Europe – spans almost 1,200 kilometres, alongside other key pieces of infrastructure, including gas pipelines and power cables.

The area that Finnish public broadcaster YLE says was cut along the Finnish-German cable is about 96 to 105 kilometers from the Lithuanian-Swedish cable that was cut, a analysis of the undersea routes shows.

It is unknown what exactly caused the failure on the C-Lion; Cinia said in a statement that it is still investigating the issue. No physical inspection has been carried out, Reuters reported, citing the company’s chief executive, Ari-Jussi Knaapila, who said at a news conference on Monday that the sudden blackout implied the cable was cut by an external force.

The foreign ministers of Finland and Germany said in a joint statement Monday night that they were “deeply concerned” about the severed C-Lion cable, and raised the possibility of “hybrid warfare.”

“The fact that an incident like this immediately raises suspicions of intentional harm says a lot about the volatility of our times. “A thorough investigation is underway,” they said in the statement. “Our European security is not only threatened by Russia’s war of aggression against Ukraine, but also by a hybrid war of malicious actors.”

The incidents come just weeks after the United States warned it detected an increase in Russian military activity around key undersea cables. Two US officials told in September that the US believed Russia was now more likely to carry out potential sabotage operations on these critical pieces of infrastructure.

The warning came after a joint research from public broadcasters in Sweden, Denmark, Norway and Finland, which reported in April 2023 that Russia had a fleet of suspected spy ships operating in Nordic waters as part of a program of possible sabotage of undersea cables and wind farms in the region.

The extent of the disruption caused by the Cinia C-Lion failure revealed Monday is unknown. Major data flows are typically routed over several different cables to avoid over-reliance on a single link.

A repair ship is ready to go to the failure site, Cinia said in a statement late Monday. He said he did not know how long repairs would take, but added that it typically takes between five and 15 days for undersea cables.

Lithuanian state media was the first to report the cut between Lithuania and Sweden, quoting Telia Lithuania’s chief technology officer Andrius Šemeškevičius as saying the cable handled about a third of Lithuania’s internet capacity. Capacity has already been restored since the interruption.

The cable is operated by Arelion, a Swedish telecommunications company. Martin Sjögren, a company spokesman, confirmed the damage to the BCS East-West link and said the company is in contact with Swedish military and civil authorities about the incident. The cable connected Gotland, Sweden, and Šventoji, Lithuania, Sjögren said.

The problem was detected on Sunday during routine 24/7 monitoring of the company’s network, and the cable is expected to be repaired in the coming weeks, depending on weather conditions, he added.

Cinia did not immediately respond to ‘s request for more details. has contacted the foreign ministries of Sweden and Lithuania for comment.

–’s Jim Sciutto contributed reporting.