Many have blamed “sabotage” for three leaks that appeared Monday in Nord Stream gas pipelines from Russia to Germany, with experts saying various armed forces in the region are capable of such an operation. Although simultaneous accidents appear out of the question, the exact method used to attack the pipelines and the identity of the perpetrator remain unclear and subject to widespread speculation. – Closely watched region – Bubbling up in international waters off the Danish island of Bornholm in the Baltic Sea, between southern Sweden and Poland, the leaks arose in what has long been one of the world’s most closely watched stretches of water. During the Cold War, “the USSR based spy submarines with special ‘seabed engineering’ capabilities in the Baltic,” independent naval analyst HI Sutton wrote on Twitter on Tuesday. Although the ex-Soviet Baltic states now belong to the NATO alliance, today’s Russian navy boasts “the largest fleet of spy submarines in the world” based in the Arctic, Sutton added. “They would be capable of damaging a pipe in the Baltic. However it seems improbable,” he wrote. Western governments have already pointed the finger at Moscow, which in turn called the allegations “absurd”. “Both branches were filled with gas, ready for pumping, and this gas is very expensive. Now this gas is disappearing into the air,” Kremlin spokesman Dmitry Peskov said Wednesday. – ‘Likely a state actor’ – It would be tough to reach the pipes beneath 70 metres of water, said Lion Hirth, professor of energy policy at the Hertie School in Berlin. “Damaging two gas pipelines on the sea floor is a major event, so it’s likely to have been a state actor,” he added, implicitly ruling out a “terrorist” or criminal attack. For a modern military, the region is “ideally suited to pocket submarines”, small craft with minimal crew, often deployed from a larger ship, a senior French military official told AFP. Divers could have been sent to the seabed to place explosives, or else self-propelled mines or a submarine drone could have done the same job. “The drone leaves from a submarine that can remain several nautical miles away from the target spot… it’s a fixed target, so it’s not too complicated” for a remote attack, the military source added. The stationary target makes it unlikely that the pipelines were struck by torpedoes fired from a submarine, which are usually used to attack moving targets, he said. Norway’s NORSAR seismology institute has estimated the size of the explosion as equivalent to 700 kilogrammes (1550 pounds) of TNT — an effect that could be produced by a more compact modern explosive. “The Baltic Sea is a confined and shallow sea, and almost any movement is tracked and observed by the littoral states and their navies,” said Julian Pawlak of Hamburg’s Helmut Schmidt University. What’s more, “NATO’s sea command and allied ships expect and prepare for hybrid activities, including sabotage of critical infrastructure,” he added. Nevertheless, “vessels and submarines are able to deploy combat divers and also unmanned underwater vehicles,” Pawlak said. A sub-sea attack would be “a special naval operation,” the French military source said. “It’s not easy, but people do it. It would have to be well coordinated and prepared.” – Vulnerability – It may be some time before a culprit can be clearly identified — leaving uncertainty that analysts say different actors are likely to exploit. The United States had long pressured Germany to reduce its dependence on Russian gas. President Joe Biden said shortly before Russia launched its invasion of Ukraine in February that “if Russia invades… I promise you we will bring an end to” the pipeline. Video of the statement has been widely shared online since the leaks, as social media users rush to find the perpetrators. The Nord Stream blasts also coincided with the opening of a new pipeline from Norway to Poland via Denmark, aimed at reducing dependence on Russian gas. “The era of Russian gas dominance is ending,” Polish Prime Minister Mateusz Morawiecki said. But Hirth said it was “hard to imagine a NATO member doing this, even the most critical about the (Russian) pipeline projects”. For now, analysts agree that the attack on Nord Stream is linked to the Ukraine war. Also certain is that the damaged pipelines add to the pressure on Europe’s economy, already thirsty for hydrocarbons to make up for lost Russian deliveries. “It is a stark reminder of the vulnerability of our energy infrastructure,” said Hirth, who himself suspects the Russians. “If that’s true, it’s pretty concerning. At the very least it means Russia is burning the bridges: It is sending the clearest possible signal it won’t deliver gas any time soon”.