Suspected sabotage by a Chinese vessel in the Baltic Sea speaks to a wider threat

Officially the Yi Peng 3 is just a bulk carrier, one of countless such ships carrying everything from grain to coal, aluminum, and fertilizer. But as she left Russia’s Baltic port of Ust-Luga last week, the Chinese-flagged ship may have had a rather different mission. Authorities and the open-source intelligence (OSINT) community have zeroed in on the Yi Peng 3 as potentially responsible for cutting two undersea cables on her journey through the Baltic Sea, and Germany’s defense minister has already called this a hybrid attack. More such incidents should be expected.

On November 17, an undersea cable connecting Sweden and Lithuania was cut, and less than twenty-four hours later, the only communications cable connecting Finland with Germany was also severed. As OSINT investigators quickly gathered, the Yi Peng 3 was at the scene both times. Swedish, Lithuanian, Finnish, and German authorities have not yet publicly blamed the bulk carrier, but as she sailed from the Baltic Sea toward Denmark’s Great Belt and from there toward the Atlantic Ocean, her actions have drawn scrutiny. By the time the bulk carrier reached the Great Belt, on November 19, she was being followed by Danish Navy vessels.

Undersea cables and pipelines are acutely vulnerable to geopolitically motivated harm.

On November 19, Germany’s defense minister, Boris Pistorius, expressed what most observers had also concluded. One had to assume, he said, that the incidents were hybrid aggression, and he described them as “sabotage.” Indeed, given that cables and pipelines are painstakingly detailed on navigational charts, it’s nearly impossible for a ship to sever not just one but two cables by accident.

This is the second time within about a year that a Chinese merchant vessel has apparently damaged undersea cables in the Baltic Sea. The last time, in October 2023, the container ship Newnew Polar Bear quickly left the scene after dragging its anchor across a gas pipeline and, it appears, two undersea cables. It then sailed through the Great Belt and continued northward along the Norwegian coast, and from there on to Russia’s Arctic coast. There wasn’t very much Sweden, Finland, or Estonia—in whose exclusive economic zones the damage had occurred—could do except ask China to cooperate in the investigation. Beijing declined their request. Was this, too, sabotage? Was the Chinese government involved? What about the Russian government? After all, Newnew Polar Bear had just left a Russian port before the cables and the pipeline were hit.

Undersea cables and pipelines are acutely vulnerable to geopolitically motivated harm, and such aggression can be carried out by persons and entities that officially have no link to the government instigating the aggression. The world’s fast-growing offshore wind farms are acutely vulnerable, too. Land-based infrastructure, for that matter, is also vulnerable, and in recent months Sweden and Finland have seen break-ins into water plants. But the world’s oceans are especially exposed. They are a global commons, guarded against military assaults by countries’ navies but otherwise protected mostly by a collection of treaties, conventions, and rules agreed by countries over the generations. (I discuss this in depth in reports for the Atlantic Council’s maritime threats project.)

At the time of writing, the Yi Peng 3 is stationary in the Kattegat, on the Danish side of this small body of water between Denmark and Sweden. She may still get away, or the Danes may decide to detain her. Regardless of the outcome, there will likely be more sabotage of undersea infrastructure in the Baltic Sea and other primarily Western waters. Each time, Western governments will face the dilemma of how to respond. For governments committed to the rule of law and the rules-based international order, it’s not enough to argue that if something looks like a duck and walks like a duck, then it’s a duck. Gray-zone aggression, in fact, presents a dilemma for the defender. (That’s why I called my book on the subject The Defender’s Dilemma.)

But being open about the threats, not to mention the attacks, is a first step. Pistorius deserves credit for saying that “nobody believes that these cables were accidentally severed” and for calling it “sabotage,” which has brought a larger public spotlight on this evolving drama. Sweden’s minister of civil defense, Carl-Oskar Bohlin, has gone further, regularly telling Swedes in no uncertain terms about the hybrid threats the country faces and exhorting citizens to do their part to thwart the power of hybrid attacks. That matters, because the attacks will continue—and not just under the sea.