Moscow said on Wednesday that training for newly mobilised reservists had started across Russia, in places including the Rostov region on the Ukrainian border and the Crimean peninsula seized from Ukraine in 2014.
The Defence Ministry said on its Telegram channel that training had also begun in the Kaliningrad exclave, which borders NATO members Poland and Lithuania.
In Rostov, where Russian forces massed before invading Ukraine on Feb. 24, the ministry said all personnel had already been "provided with the necessary clothing, received weapons and started firing training".
President Vladimir Putin last week ordered Russia's first military mobilisation since World War Two, which could see hundreds of thousands more men sent to fight in Ukraine.
In Kaliningrad, where Russia's large military presence includes nuclear-capable missiles, training began on the Baltic Fleet's base.
"Citizens called up from the reserve are restoring their skills in the operation and maintenance of weapons, and military and special equipment," the ministry said in a statement.
Courses had been also held to improve firing skills and prepare military personnel for "confident actions on the battlefield".
The ministry said about 2,000 reservists had already received weapons in Crimea, the Ukrainian peninsula that Moscow seized in 2014 and now considers part of Russia.
The mobilisation announcement has prompted many thousands of men of fighting age to try to leave Russia to avoid being called up to fight in Ukraine. (Reporting by Lidia Kelly in Melbourne; Editing by Kevin Liffey)