The Swedish Seismological Agency said on Tuesday that two underwater explosions “mostly due to explosions” were reported shortly before the Nord Stream 1 and 2 gas pipeline leaks were discovered.
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A first “massive burst” of magnitude 1.9 was recorded at 02:03 (00:03 GMT) southeast of the Danish island of Bornholm from Sunday to Monday, followed by a magnitude 2.3 at 7:04 pm (5:04 pm GMT). Monday evening in the northeast of the island, Peter Schmidt of the Swedish National Seismological Network told AFP.
“We interpret it as coming with the greatest probability from some kind of explosion,” he said.
The Norwegian Independent Seismological Agency (Norser) confirmed after recording “a small explosion” in the early hours of Monday morning and another “much more powerful” one Monday evening, which is suspected to be deliberate.
“It’s an explosion of significance. It makes you think it’s the work of someone who knows what he’s doing,” its director Ann Strommen Lig told AFP.
“With such a large energy release, there is nothing but an explosion,” said Mr. Schmidt said.
A seismologist at the Swedish University of Uppsala notes that the tremors were “very sudden”.
Three large spills identified since Monday off the Danish island of Bornholm showed bubbles 200 meters to 1 kilometer in diameter visible on the surface, according to images from the Danish military.
Ukraine said on Tuesday that the unexplained leaks were the result of a “planned terrorist attack” by Moscow “against the European Union”, raising suspicions of sabotage.
The Kremlin said it was “extremely concerned” by the leaks detected at the Nord Stream 1 and 2 gas pipelines, and considered the “no” hypothesis, including sabotage, to be excluded.
