Sweden’s coast guard this week discovered a fourth gas leak in damaged pipelines of the Nord Stream gas pipeline, a coast guard spokesman told Svenska Dagbladet newspaper, Reuters reported.

“Two of these four are in Sweden’s exclusive economic zone,” Coast Guard spokeswoman Jenny Larsson said. The other two holes are in Denmark’s exclusive economic zone.

More than half of the gas from Nord Stream 1 and 2 has already escaped into the atmosphere, Danish authorities said on Wednesday.

The European Union suspects that sabotage is behind gas leaks from Russian underwater pipelines to Europe, and has promised to respond “firmly” to any deliberate disruption of energy infrastructure.

German security services fear that Nord Stream will become permanently unusable, government sources told Tagesspiegel. They said large amounts of salt water would enter the pipelines and cause corrosion if the breaks in the two pipelines were not repaired quickly.

Russia’s FSB has launched an investigation into an “act of international terrorism” following the alleged sabotage of the Nord Stream gas pipeline in the Baltic Sea. Moscow summoned Joe Biden to say whether the US was behind the leak.

It is “ridiculous” for Russia to suggest that the United States may be responsible, White House National Security Council spokeswoman Adrienne Watson said on Wednesday.

A Swedish researcher has pointed to the “obvious culprit” in the Nord Stream gas pipeline explosions: military unit 40056.

Leaks from explosions at the Nord Stream 1 and 2 gas pipelines in the Baltic Sea are releasing methane, a powerful greenhouse gas. But while the incident is expected to have limited effects on the climate, experts say it illustrates the risks of such emissions.

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