A series of unusual leaks on natural gas pipelines extending from Russia under the Baltic Sea to Germany sparked concerns about possible sabotage on Tuesday, casting a shadow over the long-awaited pipeline opening in Poland that will bring Norwegian gas to Europe in an effort to boost energy independence. Danish Prime Minister Mette Frederiksen said she "could not rule out" sabotage after three leaks were discovered in the past day on Nord Stream 1 and 2. The pipelines are not transporting gas to Europe because the energy standoff due to the Russian war in Ukraine has halted flows. However, the pipelines are still filled with gas.

Frederiksen also joined Polish President Andrzej Duda and Prime Minister Mateusz Morawiecki in opening a valve of the Yellow pipeline belonging to the Baltic pipes, a new system that transports Norwegian gas through Denmark and the Baltic Sea to Poland. No official provided evidence for the cause of the problems, but in Central Europe, where distrust of Russia is widespread, there were concerns that Moscow had sabotaged its infrastructure as a retaliatory gesture or to indicate that all pipelines are vulnerable to attack. The leaks appeared off the coasts of Denmark and Sweden, heightening concerns about whether energy infrastructure in European waters is being targeted, leading to a slight rise in natural gas prices. A Polish government official said he would not rule out the possibility of Russia conducting "provocations." Deputy Foreign Minister Marcin Przydacz added: "I cannot rule out any scenario, we are in a very tense international situation. Unfortunately, our eastern neighbor pursues an aggressive policy at all times." Kremlin spokesman Dmitry Peskov described the leaks as "very worrying," stating in a conference call with journalists: "This is an unprecedented situation that requires urgent investigation, we are very concerned about this news." Asked whether the incident could be an act of sabotage, Peskov said, "No version can be ruled out."

Since the pipelines are not actively sending gas to Europe, the leaks do not pose a threat to energy supplies, and experts said the environmental impact would be limited. With the continent needing gas for heating homes, generating electricity, and operating factories, the energy crisis triggered by the Russian war in Ukraine threatens rationing, business closures, and potential recession this winter. In this regard, Christian Røn Poulsen, an energy analyst at the Danish company Green Power, said, "It was unusual for such a gas leak to occur." Also, Polish energy expert Andrzej Sikora said he had warned of "possible attacks on infrastructure" since Nord Stream 1 was built in 2010. It is clear that the significant pressure drop caused by the leaks was not due to "bad welding," said Sikora, head of the Energy Studies Institute's research center. Danish authorities said on Monday that a leak was detected in the Nord Stream 2 pipeline, which has never been used. They later announced a significant pressure drop on the parallel Nord Stream 1 line, which until recently was a major source of gas for Germany. The Swedish Maritime Administration also said on Tuesday that two leaks were detected in Nord Stream 1, which partly extends through Swedish waters.