NATO said that a series of leaks on the Nord Stream pipelines between Russia and Europe were the result of sabotage and that attacks on its members’ infrastructure would be met with a collective response from the military alliance.
The statement, from the North Atlantic Council, the decision-making body of the North Atlantic Treaty Organization, didn’t provide details or evidence. It also noted that the damage to the pipelines occurred in international waters. But it marks the first time the alliance has formally warned that it would deter and defend against attacks on its members’ critical infrastructure following the now four documented leaks in the Nord Stream and Nord Stream 2 pipelines.
NATO Secretary-General Jens Stoltenberg separately wrote on Twitter that the sabotage on the pipelines was of “deep concern.”
“NATO is committed to deter and defend against hybrid attacks,” he wrote. “Any deliberate attack against Allies’ critical infrastructure would be met with a united and determined response.”
At a NATO meeting Wednesday evening, Danish officials said the pipelines were damaged by several explosions Monday with the force of 500 kilograms of TNT (about 1,100 pounds), officials familiar with the discussions said.
Swedish and Danish authorities said Thursday that a total of four leaks—two in the waters of each country—had been verified. The Swedish Coast Guard said the fourth leak—the second in Swedish waters-—was discovered earlier this week around the same time as the first. The second leak is smaller, and emissions from that leak are weakening, according to the agency’s ongoing surveillance of the site.
The aftermath of the leaks threatens to expand the theater of the conflict in Ukraine, which so far has mostly been confined to Ukraine’s borders, and to conflate it with the economic war playing out between Russia and the West. While the incidents don’t affect Europe’s gas supply—the pipelines aren’t now in use—they have raised fears about the security of the continent’s energy systems as governments work to build up their gas supplies for the winter.
The North Atlantic Council, which consists of representatives from all 30 NATO governments, didn’t name a culprit behind the Baltic Sea leaks, though officials in several member countries have already attributed the destruction to Russia, without providing evidence.
Russia has denied involvement in the damage to the pipeline and the Kremlin has called it “a terrorist attack, possibly at the state level.”
Presidential spokesman Dmitry Peskov told reporters Thursday that much more NATO than Russian hardware is in the area where the pipeline leaks have occurred.
“This area is the Baltic Sea. There were many more aircraft, ships or other marine vehicles from NATO countries there,” he said. “So, these reports [of Russia’s involvement] are absolutely ridiculous…and biased.”
The council didn’t say how it arrived at its assessment that the damage, which it said has caused environmental fallout and shipping disruptions.
It said the military alliance would be prepared to defend its infrastructure from attacks by both foreign governments and individuals acting without explicit state backing.
“All currently available information indicates that this is the result of deliberate, reckless, and irresponsible acts of sabotage,” the council said. “We, as Allies, have committed to prepare for, deter and defend against the coercive use of energy and other hybrid tactics by state and non-state actors.”
U.S. officials said they were ready to help investigate the leaks.
The statement marks a ratcheting up of tensions between Russia and the West, as Russian President Vladimir Putin pushes ahead with plans to annex occupied parts of eastern and southern Ukraine. Russian officials have warned that any attack on those still-contested territories, which include areas where fighting is under way, would be considered an attack on Russia itself.
Several senior European diplomats said there was little serious doubt in capitals that Russia was behind the pipeline damage but that it was important to be absolutely certain given the implications of reaching that conclusion. During a meeting late Wednesday, NATO member countries said it was likely that Russia was responsible for the leaks, but most countries didn’t want to publicly mention their suspicions in the public statement without more evidence, these diplomats said.
Even before Thursday’s statement, leaders of Denmark and Poland publicly blamed the leaks on sabotage, as did Sweden, which is awaiting approvals from Hungary and Turkey to join the alliance.
“If it would be just one leak, this could have been an accident,” said Poland’s Deputy Foreign Minister Paweł Jabłoński. “But a situation where we have several simultaneous leaks points to an action that was purposeful. This is the main reason.”
He added, “What I can say is we certainly should take into account the possibility that Russia is behind this. While Nord Stream 2 was never operational and Nord Stream 1 was suspended, it was clear that Russia is no longer having any profits from this, so damaging this and using it as a false pretense for an escalation of the war would be something out of Russia’s playbook…especially as it could be attributed as a false-flag attack.”
NATO members have long harbored concerns about attacks on what they deem critical infrastructure, a term that has come to include telecommunications networks but also encompasses energy pipelines such as the two Nord Stream projects.
The Russian pipes have two different owners. Nord Stream is owned by a Switzerland-based company, Nord Stream AG. Its shareholders include Russia’s state-gas exporter Gazprom PJSC as well as European energy companies such as Germany’s Wintershall Dea AG and France’s Engie SA . The project, pushed by Mr. Putin and Germany’s then-Chancellor Angela Merkel, was launched in 2011 despite protests by Eastern European and Ukrainian leaders who said it would give Russia additional leverage over European energy markets. Over the next decade, it overtook Ukraine as the biggest route for Russian gas into Europe.
Ms. Merkel pursued a second subsea pipeline, Nord Stream 2, owned by a Swiss subsidiary of Gazprom, despite U.S. objections. Engineers finished laying the pipe in 2021 and it was expected to double the volume of gas that Russia could send directly to Germany. Ms. Merkel’s successor, Olaf Scholz, indefinitely suspended authorization for the pipeline days before Russia’s invasion of Ukraine in February. The U.S. has hit the company with sanctions.
The Nord Stream pipelines are vast, laid mostly along the seabed, each more than 750 miles long. The explosions were large enough to be detected by seismographs in Sweden.
The leaks raised nerves among traders about the prospect for further supply disruptions. Russia had already throttled gas exports to Europe in recent months in what European officials have called an economic attack.
—Jenny Strasburg in London contributed to this article.
Write to Matthew Dalton at Matthew.Dalton@wsj.com and Laurence Norman at laurence.norman@wsj.com
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