Russia on Thursday threatened to bolster its defences in the region, including by deploying nuclear weapons if Sweden and Finland joined the U.S. led military alliance NATO.

Finland, Prime Minister Sanna Marin on Wednesday said Finland will make a decision in the next few weeks as it shares a 1,300-km (810-mile) border with Russia, and Sweden are considering joining the NATO alliance.

Dmitry Medvedev, deputy chairman of Russia’s Security Council, said that should Sweden and Finland join NATO then Russia would have to strengthen its land, naval and air forces in the Baltic Sea.

Medvedev also explicitly raised the nuclear threat by saying that there could be no more talk of a “nuclear free” Baltic – where Russia has its Kaliningrad exclave sandwiched between Poland and Lithuania.

“There can be no more talk of any nuclear free status for the Baltic, the balance must be restored,” said Medvedev, who was president from 2008 to 2012.

“Until today, Russia has not taken such measures and was not going to,” Medvedev said. “If our hand is forced well take note it wasn’t us who proposed this,” he added.

Lithuania said Russia’s threats were nothing new and that Moscow had deployed nuclear weapons to Kaliningrad long before the war in Ukraine.

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 World War Two during which it lost some territory to Moscow.

On Thursday, Finland announced a military exercise in Western Finland with the participation of forces from Britain, the United States, 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. (Reuters/NAN)