Investigators found traces of subsea explosives in samples taken from a boat that has been one aspect of a probe into the sabotage of the Nord Stream gas pipelines under the Baltic Sea last year, European diplomats have told the U.N. Security Council.

Investigators found traces of subsea explosives in samples taken from a boat that has been one aspect of a probe into the sabotage of the Nord Stream gas pipelines under the Baltic Sea last year, European diplomats have told the U.N. Security Council. (Swedish Coast Guard)

It’s been one year since underwater explosions severely damaged the Nord Stream pipelines built to carry natural gas from Russia to Europe, inflaming geopolitical tensions that were already heightened by the invasion of Ukraine.

The attack on Sept. 26, 2022, which ruptured the conduit between Russia and Germany, was quickly denounced by Western officials as a brazen and dangerous act of sabotage. The implications were significant: An attack on the critical infrastructure of a member state threatened to draw the European Union and NATO into the war and came at a time when Europe was still working to wean itself from its dependence on Russian energy.

Shortly after the attack, one expert likened the situation to an Agatha Christie mystery, in which all parties involved — namely Russia and Ukraine — appeared to have a motive or could have benefited from the outcome.

In the months since, however, official investigations in three countries have yielded few answers, and the question of who was behind the blasts endures.

Here is what we know about the investigations, one year later.

What happened to Nord Stream 1 and Nord Stream 2?

On Sept. 26, 2022, explosions damaged the Nord Stream 1 and Nord Stream 2 pipelines in the Baltic Sea, leaving only one gas link in the network intact. The three damaged sections contained 778 million cubic meters of natural gas, according to the Danish Energy Agency, and the resulting spill was probably one of the largest single leaks of methane gas into the atmosphere, experts said.

The explosions took place in international waters off the coast of the Danish island of Bornholm.

“These are deliberate actions, not an accident,” Danish Prime Minister Mette Frederiksen told reporters after the incident. “The situation is as serious as it gets.”

The attack created a global stir but did not have an immediate effect on Europe’s energy supply.

The Russian state-owned energy company Gazprom had ended gas supply on Nord Stream 1 in early September 2022, when it was still operational. The Nord Stream 2 project was suspended in February 2022, after Germany halted authorization of the pipeline in the lead-up to Russia’s invasion of Ukraine.

The $11 billion Nord Stream 2 pipeline had been controversial, and the Ukrainians, as well as U.S. leaders, worried that the project would grant Russia too much leverage over energy security in Europe. Ukraine, which had long played the middleman and routed Russian gas to Europe for transit fees, worried that Russia would use the project to further isolate it.

Who blew up the Nord Stream pipelines?

That remains unclear. While some officials maintain that the operation was complex and could have been carried out only by a nation-state, others cite the shallow depth of the pipelines to point to the possibility of non-state actors. What everyone agrees on is that the attack was deliberate.

Moscow and Kyiv have both denied responsibility.

U.S. and European officials initially blamed Russia, but that thinking changed as investigations gathered pace.

In December 2022, one European official said no conclusive evidence at that point suggested Russian involvement, The Washington Post reported, a view that was echoed by nearly two dozen diplomatic and intelligence officials in nine countries. Some other Western intelligence has shown that Russian naval vessels were detected around the attack locations in the weeks before the blasts.

Questions have also emerged over Ukraine’s culpability because it had longed opposed the Kremlin-backed pipelines.

German investigators homed in on the role of a 50-foot yacht called the Andromeda that had been chartered under a false identity. Authorities suspected the boat was used to transport explosives used in the attack.

In March, Western officials told The Post that some information — based on intelligence communications — suggested the hand of a pro-Ukraine group, possibly operating without the direct knowledge of Kyiv.

The Post reported in June that the CIA had learned from an ally months before the explosions that the Ukrainian military had planned a covert attack on the Nord Stream pipelines, according to leaked intelligence documents shared on the chat platform Discord.

Last month, the German newspaper Der Spiegel, along with German public broadcaster ZDF, published a months-long investigation from around the globe. All the leads, the report said, pointed toward Kyiv, calling the findings “politically sensitive.”

German investigators have called the operation an attack “on the internal security of the state,” Der Spiegel said, adding that it was aimed at “inflicting lasting damage.”

In February, American journalist Seymour Hersh alleged in an article on Substack that U.S. Navy divers, operating under cover of a NATO exercise with Norway in the Baltic Sea, had placed explosives on the two pipelines in the summer of 2022 and later were ordered to blow them up in response to Russia’s invasion of Ukraine.

The Biden administration categorically denied the allegation. Hersh’s account was based on a single anonymous source, and no other media outlet has corroborated it.

What is the status of the investigations into the sabotage?

Germany, Denmark and Sweden have separately opened investigations into the attack and continue to cooperate on the matter.

“The nature of the acts of sabotage is unprecedented and the investigations are complex,” the three countries said in a letter to the U.N. Security Council in July. Russian authorities have been apprised on the developments, it said.

The investigation in Germany is being helmed by the public prosecutor general of the Federal Court of Justice along with the national police. The investigation is ongoing, and it was not possible yet to establish the identity of the perpetrators or whether the act was carried out by a state or state actor, Germany said in the letter to the United Nations.

Sweden’s security service is the lead agency inquiring into the matter under public prosecutor Mats Ljungqvist, and the country made “extensive seizures” from the crime scene, it has said.

“We hope to conclude the investigation shortly, but there is still a lot to do, and nothing will happen for the next four weeks,” Ljungqvist told Reuters last week. He had earlier said the “main scenario” included a state actor’s involvement, the report said.

Meanwhile, security, intelligence and police agencies have been involved in Denmark’s investigation and are working with foreign authorities.

Russia has sought a U.N. investigation into the matter.

What will this mean for the war in Ukraine?

Stefan Meister, an expert on E.U.-Russia relations at the German Council on Foreign Relations, said in an email that Europe would not stop supporting Ukraine regardless of who is responsible. The pipelines are history, and Russia’s actions in Ukraine are what matter now, he said.

“We are now in a different stage ... with Russia and Ukraine, where this gas connection matters less,” he wrote, adding that Ukraine not losing the war was of greater importance.

The attack, however, has made Europe rethink the security of its critical infrastructure, Meister said.

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