Putin asserts his nation's ownership of 460,000 square miles of Arctic territory - and its huge reserves of oil and gas - after exploration feat of 'unimaginable difficulty'

Russia has taken a giant leap for the Kremlin by planting its flag on the ocean floor under the North Pole in a politically charged symbolic gesture to claim the rights to the sea bed which could be rich in oil and gas. In a dramatic technical feat testing international law, the Russians dispatched two mini-submarines 2.5 miles to the ocean floor in what is believed to be the first expedition of its kind. Both submersibles, with crews of three on board, completed their dangerous return to the surface yesterday after what was described as a "smooth landing".

But the expedition raised the hackles of Russia's neighbours, who also have their eye on the vast mineral deposits that could lie under the Arctic area, and who consider the Russian move as a brazen land grab. "This isn't the 15th century. You can't go around the world and just plant flags and say 'We're claiming this territory'," said Peter MacKay, Canada's Foreign Minister.

Russia has fired the first diplomatic shot in a really cold war. The new oil rush has been galvanised by the accelerated shrinking of the polar ice cap because of global warming, which has allowed exploration that had been previously unthinkable because of the extreme conditions.

Russia claims that the Lomonosov Ridge, an underwater mountain range crossing the polar region, is an extension of its territory. The UN has rejected Moscow's 2001 claim to the ocean bed, which it says is part of its continental shelf under international law but the Russians are due to resubmit their case to the committee administering the Law of the Sea.

A brains trust of 135 Russian scientists, led by a 68-year-old personal envoy of President Vladimir Putin, the explorer Artur Chilingarov, plan to map out part of the 1,240-mile ridge. But yesterday's scientific achievement of dropping a titanium capsule containing the Russian flag on to the seabed could not conceal the political advantage gained by Mr Putin. Once again, he has demonstrated to the West Russia's determination to expand its energy empire.

The news of the mission's success dominated Russian television yesterday. Dmitry Peskov, Mr Putin's spokesman, said the President considered it "very important ... Being a unique scientific expedition, it is of course supported by the President." The Foreign Minister, Sergei Lavrov, said: "I think this expedition will supply additional scientific evidence for our aspirations." But he added that the issue of territorial claim to the polar region "will be resolved in strict compliance with international law". If recognised, the claim would give Russia control of nearly half of the Arctic's near-half million square mile sea bed.

But four other countries - the US, Canada, Norway and Denmark - also have claims on the ocean floor which could hold as much oil and gas as Saudi Arabia. According to the US Geological Survey, the Arctic seabed and subsoil account for 25 per cent of undiscovered oil and gas reserves.

The Russian convoy, consisting of a research vessel and a nuclear-powered ice-breaker, and the two submersibles which had been used in the filming of Titanic, set sail from the northern Russian city of Murmansk last week, catching the world by surprise. Initial concerns that the expedition could be thwarted by thick sea ice proved unfounded, although the research vessel, the Akademik Fyodorov suffered from engine trouble on the journey.

Mr Chilingarov was on board the Mir-1, the first submersible to go down, and spent eight hours and 40 minutes under water. The last 40 minutes were tense, as the crew tried to find an opening free of ice. "It was so good down there," he said on his triumphant return. "If someone else goes down there in 100 or 1,000 years, he will see our Russian flag." The Mir-2 had an international crew on board, including the Australian deep-sea specialist Mike McDowell who previously led tours to the Antarctic. The co-sponsor of the voyage, the Swedish pharmaceuticals millionaire Frederik Paulsen, was also on the submersible, according to the Russian news agency Itar-Tass.

In addition to the engineering challenge - which has been compared to the first moon landing - the dark depths of the Arctic waters are so mysterious that the Russian crew did not know what they would find.

Vladimir Gruzdev, who accompanied Mr Chilingarov on Mir-1, mused before their dive: "What if we encounter Atlantis there? Nobody knows what is there. We must use the opportunity given to us 100 per cent." The operation was straight out of a Jules Verne story, with expectations that exotic underwater creatures would appear from the uncharted depths. But in a momentous anti-climax, the expedition's leader declared: "There is yellowish gravel down here. No creatures of the deep are visible."

While in the Arctic, until mid-September, the scientists will continue to study in detail the climate, geology and biology of the polar region. But the Russians had better watch their backs: the Danes hope to prove that the Lomonosov Ridge is an extension of Greenland, which is part of Denmark. Canadian and Danish scientists are currently on two icebreakers mapping the north polar sea.

And in a reminder of the Kremlin's aggressive use of its oil and gas wealth, the state-run Gazprom this week threatened to cut off gas to Belarus in a re-run of the economic bullying of Ukraine in 2006 that affected further supplies to Europe. Belarus owes Russia $460m for gas. Alexander Lukashenko, Belarus's President, yielded to the demand yesterday, after being promised a little help by the Venezuelan President, Hugo Chavez. If Russia had carried out its threat, gas supplies to Germany and Poland would definitely have been at risk.

(By Anne Penketh, The Independent, 03/08/2007)