Russian President Vladimir Putin has accused the West of sabotaging Russian-built gas pipelines under the Baltic Sea to Germany, a charge that has been vehemently denied by the US and its allies.

Nordic nations said the undersea blasts that damaged the pipelines this week and led to huge methane leaks involved several hundred pounds of explosives.

The claim by Mr Putin came ahead of an emergency meeting at the UN Security Council in New York on the attacks on the Nord Stream 1 and 2 pipelines.

Norwegian researchers published a map projecting that a huge plume of methane released by damaged pipelines will travel over large stretches of the Nordic region.

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Vladimir Putin (Mikhail Metzel, Sputnik, Kremlin Pool Photo/AP)

Speaking on Friday in Moscow, Mr Putin claimed that “Anglo-Saxons” in the West have turned from sanctions on Russia to “terror attacks”, sabotaging the pipelines in what he described as an attempt to “destroy the European energy infrastructure”.

He added that “those who profit from it have done it”, without naming a specific country.

Moscow says it wants a thorough international investigation to assess the damage to the pipelines, which carry Russian natural gas to Europe.

Mr Putin’s spokesman said: “It looks like a terror attack, probably conducted on a state level.”

European nations noted that it is Russia, not Europe, that benefits from chaos in the energy markets and spiking prices for energy.

Even before Mr Putin’s comments, US State Department spokesman Ned Price strongly rejected any claims that the US might have sabotaged the Nord Stream pipelines.

“The idea that the United States was in any way involved in the apparent sabotage of these pipelines is preposterous. It is nothing more than a function of Russian disinformation and should be treated as such,” he said on Wednesday.

The US has long been opposed to the two pipelines and had repeatedly urged Germany to halt them, saying they increase Europe’s energy dependence on Russia and decrease its security.

Since Russia’s invasion of Ukraine in February, European nations have charged that Mr Putin is using “energy blackmail” and reducing gas flows to Europe to divide EU support for Ukraine.

Nord Stream 2 is a 764-mile natural gas pipeline under the Baltic Sea, running from Russia to Germany’s Baltic coast. It runs parallel to an earlier Nord Stream pipeline and would double its capacity, to 110 billion cubic meters of gas a year.

It was built so Russian energy giant Gazprom could send gas to Europe’s pipeline system without using existing pipelines that run through Ukraine and Poland.

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A gas leak in the Baltic Sea (Swedish Coast Guard/AP)

Denmark and Sweden said on Friday that the explosions that rocked the Baltic Sea ahead of the huge methane leaks “probably corresponded to an explosive load of several hundred kilos”.

The leaks occurred in international waters and “have caused plumes of gas rising to the surface”, said the letter by the two Scandinavian countries’ missions to the UN.

Nato warned on Thursday that it would retaliate for any attacks on the critical infrastructure of its 30 member countries and joined other western officials in citing sabotage as the likely cause of damage.

Denmark is a Nato member and Sweden is in the process of joining the military alliance. Both say the pipelines were deliberately attacked.

The Integrated Carbon Observation System, a European research alliance, said on Friday that “an enormous amount of methane gas has been released into the atmosphere”, adding that it corresponds to the size of a whole year’s methane emissions for a country like Denmark.

“We assume the wind in the leak area blew the methane emissions north to the Finnish archipelago, then (the emissions) bend toward Sweden and Norway,” said Stephen Platt, a professor with the Norwegian Institute for Air Research, part of the group.

The data was gathered from ground-based observations from stations in Sweden, Norway, and Finland. Experts say these methane levels are not dangerous to public health but are a potent source of global warming.

The suspected sabotage this week on the Nord Stream 1 and 2 pipelines produced two methane leaks off Sweden, including a large one above Nord Stream 1 and a smaller one above Nord Stream 2, and two leaks off Denmark.

Nordic seismologists recorded explosions preceding the leaks. A first explosion was recorded early on Monday south east of the Danish island of Bornholm. A second, stronger blast north east of the island that same night was equivalent to a magnitude 2.3 earthquake.