The authorities in Germany, Denmark and Sweden are investigating suspicious leaks in two gas pipelines running from Russia to Germany under the Baltic Sea, after both experienced a sudden drop in pressure that raised concerns among European leaders on Tuesday about possible sabotage.
Neither of the pipelines, Nord Stream 1 and 2, had been active, but both were filled with natural gas when they experienced a sharp drop in pressure that was first registered on Monday.
Footage released by the Danish Defense command showed a swirling mass of methane bubbling up onto the surface of the Baltic Sea. The authorities said the drop could only be caused by a leak, and officials in Denmark raised its security alerts at electricity and gas facilities around the country.
Mateusz Morawiecki, Poland’s prime minister, blamed Russia for the leaks, saying they were an attempt to further destabilize Europe’s energy security. He spoke at the launch of a new undersea pipeline that connects Poland to Norway through Denmark.
“We do not know the details of what happened yet, but we can clearly see that it is an act of sabotage,” Mr. Morawiecki said. “An act that probably marks the next stage in the escalation of this situation in Ukraine.”
Denmark’s prime minister, Mette Frederiksen, said that sabotage could not be ruled out. “It is too early to conclude yet, but it is an extraordinary situation,” she said during a visit to Poland to inaugurate the pipeline from Norway.
“There is talk of three leaks, and therefore it is difficult to imagine that it could be accidental,” she said.
Mykhailo Podolyak, a senior adviser to President Volodymyr Zelensky of Ukraine, said on Twitter that the leaks were “a terrorist attack planned by Russia and an act of aggression towards E.U.”
The Kremlin’s spokesman, Dmitri S. Peskov, said of the leaks that “no possibility can be ruled out,” but the Russian state media sought to blame the United States and Ukraine. The state-run RIA Novosti news agency reported that Washington “is an active opponent of Russian gas supplies to Europe,” and said that Ukraine opposed Nord Stream 2 because it “was afraid of losing revenues from the transit of Russian gas.”
It was not immediately clear who would benefit from ruptures in the pipelines, which were not in operation. The leaks were found at different points on two branches of the Nord Stream 1 pipeline and one branch of Nord Stream 2, Danish and Swedish officials said. They warned ships to avoid the affected areas.
The pipelines have been a focal point of the broader confrontation between Russia and Europe. After the European Union imposed economic sanctions on Russia to penalize it for invading Ukraine in February, Russia began withholding the natural gas that for decades it had sent to Europe, threatening the continent’s energy supply as winter looms.
The governments in Denmark and Germany both said the leaks would not affect natural gas supplies in their countries. Gazprom had already halted nearly all deliveries of natural gas to Europe, through Nord Stream 1 as well as all but one of several overland pipelines, and European countries have turned to other suppliers, including Norway, to meet their energy needs.
But the incident made clear how vulnerable energy infrastructure could be. Norway’s Petroleum Safety Authority warned on Monday that unidentified drones had been sighted recently near its offshore oil and gas facilities, raising concerns of possible explosions, helicopter collisions or of “deliberate attacks.” It called for “increased vigilance by all operators and vessel owners,” citing the heightened security concerns following recent threats by Russia linked to its war in Ukraine.
Russia’s Gazprom halted deliveries through Nord Stream 1 indefinitely earlier this month, as part of a continuing dispute with Germany over gas deliveries. Nord Stream 2 was never put into operation after Germany canceled its certification on the eve of Russia’s invasion of Ukraine.
Senators and members of Congress had lobbied for years to impose sanctions on Nord Stream 2. After Germany halted certification, President Biden imposed sanctions on the Russian-owned operator of the pipeline.
Germany’s energy ministry said in a statement on Monday that a grid operator had reported “a sharp drop in pressure” in Nord Stream 2. The Danish Maritime Authority said the leak appeared to have occurred off the coast of a Danish island and issued a navigation warning for the area.
Separately, the operator of Nord Stream 1 said it had detected a pressure drop that was later confirmed by the German economy ministry. The pipeline is made up of about 100,000 concrete-coated steel pipes designed to withstand the change in pressure the gas undergoes on the 760 mile journey from Russia to Germany. They lie on the floor of the Baltic Sea.
Monika Pronczuk, Oleg Matsnev and Torben Brooks contributed reporting.
