Stockholm, 6 October 2022 (dpa/MIA) - Swedish prosecutors said on Thursday that they are now sure that explosions caused the holes that caused underwater leaks in the Nord Stream 1 and 2 gas pipelines. The detonations caused "extensive damage" to the pipelines, prosecutors and the Swedish Security Service announced in Stockholm. "The investigation has strengthened the suspicions of gross sabotage," the Security Service said. Large quantities of gas leaked from a total of four leaks on the pipelines - two of them in Swedish waters, two in Danish waters. The pipelines were filled with Russian gas, but were not actually delivering gas to Europe due to the consequences of the war in Ukraine and tensions with Russia. The Swedish authorities said they would continue to monitor developments closely and do everything possible to ensure Sweden's safety. Several countries had already said that they assumed the pipelines had been sabotaged. Seismological institutes in Scandinavia measured a shock of magnitude of 2.3 and 2.1, which corresponded to "several hundred kilograms of explosives." Items were confiscated at the scene which will now be further examined, the prosecutors said. The cordons around the leaks have been lifted in the meantime. For several days, an area 5 nautical miles (just under 9 kilometres) wide had been closed off to shipping and other activities. Nord Stream 1 and 2 each consist of two parallel pipes. Both strands of Nord Stream 1 were damaged in the blasts, and one strand of Nord Stream 2. The operator of Nord Stream 2 said on Thursday that it was releasing some of the gas in the remaining intact pipe. This was a precautionary measure following the damage to the other three strands, he said. Up until now an operational pressure of 105 bar had been maintained in the pipe. The Nord Stream 2 operator is a subsidiary of Russia's state-owned energy firm Gazprom.