Russia is still analysing the steps it will take to bolster its security should Finland and Sweden join NATO, says Deputy Foreign Minister Alexander Grushko.
He said the Nordic countries' membership in the Western defence alliance would prompt "strategic changes," but that it was still too early to talk about the possibility of Russia stationing nuclear weapons in the Baltic region, according to the Interfax news agency.
Former president Dmitry Medvedev, who is now deputy head of the National Security Council in Moscow, had threatened to station nuclear weapons in Russia's Baltic exclave of Kaliningrad.
Long-neutral Finland is now close to applying for NATO membership out of concern for its own security because of Russia's invasion of Ukraine.
Finland's joining would double NATO's border with Russia in one fell swoop.
The EU's northernmost country has a border with Russia that is more than 1,300 kilometres long.
Sweden, traditionally a non-aligned country, could also change its mind. A decision is expected to be made by the government there soon.
Grushko said that if NATO deploys nuclear weapons on Russia's borders, Moscow will respond accordingly.