The 12-day "Freezing Winds" exercise is part of the transatlantic defense alliance's efforts to boost defense of infrastructure in waters that account for 15 percent of global shipping traffic and are seen as increasingly vulnerable to attack.
The Baltic Sea borders eight NATO countries and Russia. There have been at least three incidents involving more than 40 important telecommunications cables and gas pipelines on the Baltic Sea floor since 2022.
“NATO is increasing patrols. Allies are investing in advanced technologies that can help better secure these assets,” said Arlo Abrahamson, a spokesman for NATO’s Allied Maritime Command.
However, the ease with which ship anchors can cut cables, coupled with often dangerous sea conditions, makes preventing such attacks nearly impossible.
Security sources said the Chinese ship Yi Peng 3 was suspected of cutting cables in Sweden's exclusive economic zone, in the area near the Nord Stream pipeline, between November 17 and 18 by dragging its anchor on the seabed.
Earlier this week, the Chinese ship remained stationary in Danish waters, monitored by naval vessels from NATO members and urged by Sweden to return for investigation.
The incident is similar to one that occurred last year when the Chinese ship NewNew Polar Bear severed two cables connecting Estonia to Finland and Sweden, as well as the Estonia-Finland gas pipeline. A year on, Finnish and Estonian investigators have yet to reach a conclusion about who was responsible.
Cable breaks are nothing new. Globally, about 150 cables are broken each year, according to the UK-based International Cable Protection Committee. TeleGeography, a US-based telecommunications research firm, notes that telecommunications cables, power lines and gas pipelines in the shallow Baltic Sea are particularly vulnerable due to heavy shipping traffic.
If any of the recent incidents are proven to have been sabotaged by another country, it would mark the return of a type of warfare not seen in decades.
State-sponsored sabotage of submarine cables often occurred during World War I or the Spanish-American War, notes Paul Brodsky, a senior researcher at TeleGeography.
To counter this potential threat, NATO opened the Maritime Centre for Critical Undersea Infrastructure Security (CUI) in London, UK in May this year. The centre is expected to map all critical infrastructure in NATO-controlled waters and identify vulnerabilities.
In Rostock, on Germany's Baltic coast, a multinational naval headquarters opened in October to protect NATO members' interests at sea.
“What I think we can achieve is accountability after an incident,” said CUI Branch Manager Pal Bratbak, highlighting the growing power of technology.
NATO's Maritime Research and Testing Center in Italy is rolling out software that combines data with personal and military imagery from hydrophones, radar, satellites, ships' AIS systems and cables with DAS sensors often used by private telecommunications companies to locate breaks in cables.
