On September 26, 2022, a series of clandestine bombings resulted in underwater gas leaks from the Nord Stream 1 and Nord Stream 2 natural gas pipelines. Both pipelines were built to transport natural gas from Russia to Germany through the Baltic Sea, and are majority owned by the Russian majority state-owned gas company, Gazprom.

Who blew up the underwater natural gas pipelines is unclear. Fingers have been pointed at pro-Ukrainian groups, covert operators from the United States Navy, and most recently a Russian Navy mini-submarine.

In early March, the New York TImes reported that intelligence reviewed by U.S. officials suggests that a pro-Ukrainian group carried out the attack on the Nord Stream pipelines.

They reported that U.S. officials said that they had no evidence President Volodymyr Zelensky of Ukraine or his top lieutenants were involved in the operation, or that the perpetrators were acting at the direction of any Ukrainian government officials.

Previously, investigative journalist Seymour Hersh claimed that the United States executed a covert sea operation that sabotaged the pipeline. Asked for comment, Adrienne Watson, a White House spokesperson, said in an email, “This is false and complete fiction.” Tammy Thorp, a spokesperson for the Central Intelligence Agency, similarly wrote: “This claim is completely and utterly false.”

Recently, it has been asserted that the Russian Navy operated a mini-submarine at the Nord Stream gas pipelines days before the explosions, according to German reports.

Citing security sources, the publication t-online suggests a unit of the Russian navy is said to have operated “like a ghost” without transmitting location data and placed explosive devices at the pipeline.

It suggests there may have been suspicious activity detected in the area in the days leading up to the attack on two gas pipes on September 26 last year, which destroyed pipes that sent natural gas from Russia to Germany along the bottom of the Baltic Sea.

Explosive charges could have been attached to the pipelines using the mini-submarine, experts suspect.

“It would make absolute sense to use something like the ‘AS-26’ for such an attack,” Danish corvette captain and military analyst Johannes Riber told t-online.

“That would be the most plausible explanation so far for what happened to the Nord Stream pipeline.”

The mini-submarine is usually part of the Russian Navy’s Baltic Fleet but publicly available satellite imagery seen by t-online shows that it left the port on September 21, along with two other ships suspected to be involved in the operation.

The US and Nato have called the September 26 attacks “an act of sabotage”, while Russia has blamed the West and called for an independent probe.

A resolution put forward last Monday by Russia at the United Nations calling for an international investigation into the apparent sabotage last year on the Nord Stream gas pipelines has failed to win Security Council support and led to more finger-pointing between the U.S. and Russian envoys.

Thanks to David Rye for contributing to this post.