Russia will establish 12 new military bases in the west of the country in response to Sweden and Finland applying for NATO membership.
Defence Minister Sergei Shoigu made the announcement on Friday, saying that the new bases would be in place "by the end of the year".
He said "12 military bases and units will be deployed in the Western Military District", telling senior ministry and army officials that there was a "growth of military threats on Russia's borders", blaming NATO and the United States.
Russia's Interfax news agency reports that Moscow is taking "adequate countermeasures" in response to those perceived "military threats" in the west.
This week Finland and Sweden both formally applied for NATO membership, a move that was unthinkable before Russia's invasion of Ukraine on 24 February.
Finland shares a 1,300km land border with Russia, while the Swedish island of Gotland is strategically important in the Baltic Sea, and only 300km from the militarised Russian exclave of Kaliningrad.
Russia considers letting over-40s sign up for military duty
In a sign of the Kremlin's urgent need to bolster its war effort in Ukraine, Russia's parliament said on Friday it would consider a bill to allow Russians over 40 and foreigners over 30 to sign up for the military.
The website of the State Duma, parliament's lower house, said the move would enable the military to utilise the skills of older professionals.
"For the use of high-precision weapons, the operation of weapons and military equipment, highly professional specialists are needed. Experience shows that they become such by the age of 40–45," it said.
Previously only Russians aged 18-40 and foreigners aged 18-30 could enter into a first contract with the military.
Russia has suffered huge setbacks and heavy losses of men and equipment in the 86-day-old war, prompting Western military analysts to say it urgently needs to mobilise more soldiers.
The Duma said the planned initiative would also make it easier to recruit civilian medics, engineers and operations and communications specialists.