(The Hill) – Russia is warning of new nuclear deployments in the Baltics if Finland and Sweden join NATO, as the two countries inch closer to becoming part of the military alliance.

Dmitry Medvedev, the deputy chairman of Russia’s Security Council and former president of Russia, wrote in a Telegram post on Thursday that “there can be no talk of non-nuclear status for the Baltic” if Finland and Sweden join NATO.

He said that should Finland and Sweden join NATO, Moscow would need to “seriously strengthen the grouping of land forces and air defense, deploy significant naval forces in the waters of the Gulf of Finland.”

“In this case, it will no longer be possible to talk about any nuclear-free status of the Baltic — the balance must be restored,” he addedaccording to CNBC.

Medvedev said that previously “Russia has not taken such measures and was not going to,” according to Reuters.

“If our hand is forced well … take note it wasn’t us who proposed this,” he added.

The cautionary statement from one of Russian President Vladimir Putin’s closest allies comes after Finland and Sweden made progress in their paths to joining NATO. Lawmakers in Finland were issued a security report by the country’s government, and the ruling party in Sweden started a review of options for security policy, according to The Associated Press.

Finland borders Russia. Sweden, however, does not share a border with Russia. Norway, which borders Sweden and shares a small border with Russia in its far northeast, joined the military alliance in 1949.

Lithuania said that the warning from Russia is not new, stating that Moscow has positioned nuclear weapons in Kaliningrad, the Russian province between Poland and Lithuania, since before the conflict with Ukraine began, according to Reuters.

Medvedev on Thursday said that if Finland and Sweden join NATO, Russia’s borders with alliance members will have to be bolstered.

“If Sweden and Finland join NATO, the length of the alliance’s land borders with the Russian Federation will more than double. Naturally, these borders will have to be strengthened,” he said, according to CNBC.

He noted that the addition of Finland and Sweden to NATO would give Russia “more officially registered opponents,” according to CNBC.

Russia began its invasion of Ukraine on Feb. 24, when Putin ordered a “special military operation” in the country. The conflict entered its seventh week on Thursday.