Russia hypersonic and nuclear weapons warning if Sweden and Finland join Nato

Dmitry Medvedev said Moscow would be forced to 'strengthen' its defences in the Baltic Sea

A Russian Navy warship during artillery drills in the Baltic Sea in January. Reuters

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Moscow has warned Nato that if Sweden and Finland join the military alliance Russia will consider bolstering its defences in the Baltic Sea with nuclear weapons.

Dmitry Medvedev, deputy chairman of Russia's Security Council, said if the nations joined the US-led military group it would be forced to strengthen its military presence with hypersonic missiles and nuclear weapons.

The warning comes hours after Russia suffered a blow in its offensive against Ukraine when its flagship missile cruiser in the Black Sea suffered serious damage in what Ukraine claims was a missile attack.

Finland, which shares a 1,300-kilometre border with Russia, and Sweden have announced they are considering joining Nato, and will make a decision in the coming weeks.

It has led Mr Medvedev to give a warning that there can be no more talk of a “nuclear free” Baltic.

“There can be no more talk of any nuclear-free status for the Baltic — the balance must be restored,” he said.

“Until today, Russia has not taken such measures and was not going to.

“If our hand is forced, well, take note it wasn't us who proposed this.”

Mr Medvedev said he hoped Finland and Sweden would see sense. If not, he said, they would have to live with nuclear weapons and hypersonic missiles close to home.

Russia has the world's biggest arsenal of nuclear warheads and along with China and the US is one of the global leaders in hypersonic missile technology.

Deputy chairman of Russia’s Duma parliament Pyotr Tolstoy backed up Mr Medvedev threats.

“[If Finland joins Nato] Russia will guarantee its security in such a way so that even a mosquito wouldn’t want to fly to our border,” he told ITV News.

However, on Thursday Lithuania's Defence Minister Arvydas Anusauskas described their comments as empty threats. He said Russia already had nuclear weapons in its exclave of Kaliningrad on the Baltic Sea.

Kremlin spokesman Dmitry Peskov declined to comment on the possibility nuclear weapons might be deployed in the Baltic region but said that President Vladimir Putin has already ordered the military to prepare plans for boosting defences along Russia’s western frontiers.

“Nuclear weapons have always been kept in Kaliningrad. The international community, the countries in the region, are perfectly aware of this,” Mr Anusauskas told news group BNS.

The possible accession of Finland and Sweden into Nato — founded in 1949 to provide collective western security against the Soviet Union — would be one of the biggest European strategic consequences of the war in Ukraine.

Finland gained independence from Russia in 1917 and fought two wars against it during the Second World War during which it lost some territory to Moscow.

On Thursday, Finland announced a military exercise in western Finland with the participation of forces from the UK, US, Latvia and Estonia.

Sweden has not fought a war for 200 years and post-war foreign policy has focused on supporting democracy internationally, multilateral dialogue and nuclear disarmament.

Russia's invasion of Ukraine suffered a setback on Thursday when its flagship missile cruiser in the Black Sea, Moskva, was seriously damaged and its crew evacuated following an explosion that a Ukrainian official said was the result of a missile strike.

Russia's Defence Ministry said a fire on the vessel had caused ammunition to blow up, Interfax news agency reported.

It did not say what caused the fire but said the warship had not sunk and “remains afloat".

Maksym Marchenko, the Ukrainian governor of the region around the Black Sea port of Odesa, said the Moskva had been hit by two Ukraine-made Neptune anti-ship cruise missiles.

The Moskva is the second major ship known to have sustained serious damage since the start of the war. Last month, Ukraine said it had destroyed a landing support ship, the Orsk, on the smaller Sea of Azov.