How NATO patrols the sea for suspected Russian sabotage

Aboard the HNLMS Luymes—Belgian Navy Commander Erik Kockx was patrolling the Baltic Sea recently when he got word that a ship on NATO's watch-list was acting in a suspicious manner. After leaving a Russian port, it had slowed down while passing near a pipeline on the sea bottom. The Luymes sailed toward the tanker to investigate.

- Daniel Michaels

Kockx leads a task force in the North Atlantic Treaty Organization's new mission to police the inland sea that its members share with Russia. NATO in January launched the operation, dubbed Baltic Sentry, after a string of undersea cables and pipelines were damaged by ships—many with links to Russia—that had dragged their anchors.

"We are functioning as security cameras at sea," said Kockx, whose usual duty is clearing unexploded mines from the busy waterway. No proof has been found that Moscow ordered or orchestrated the destruction, according to officials familiar with the investigations, though suspicion of it runs high in NATO countries.

Baltic Sentry taps at least 10 ships under NATO command at any given time and splits them into two task groups. It also uses many more ships from the navies, coast guards and police forces of the eight alliance countries bordering the Baltic. New undersea drones are keeping a watchful eye on pipes and cables. NATO surveillance planes from the U.S., France, Germany and occasionally the U.K. take turns scanning the seaway from high above. NATO has also strengthened its military presence on the Baltic, said U.S. Army Gen. Christopher Cavoli, who serves as supreme allied commander for Europe and launched the mission.

Many of the units involved were already performing similar duties. Now they communicate and cooperate much more, orchestrated by the Centre for Critical Undersea Infrastructure that NATO's Allied Maritime Command established last year, officials say.

Baltic Sentry has largely relied on European forces, but late last month a U.S. Marine Corps detachment of around 40 Marines arrived in Finland for what NATO calls vigilance exercises, entailing drones and small craft. The unit, which is operating alongside Finnish forces, is practicing small-island skills that could prove useful in other regions, such as the Pacific, officials say.