Russian Defense Minister Sergei Shoigu says more than 200,000 people have been drafted into Russia's armed forces since President Vladimir Putin ordered a partial mobilization on September 21.
"As of today, more than 200,000 people have entered the army," Shoigu said during a televised meeting on Tuesday.
He said those who had been mobilized were being trained at "80 training grounds and six training centers."
The Kremlin announced plans to enlist 300,000 men with previous military experience to bolster Russia's military offensive in Ukraine.
Shoigu also demanded that military and navy commanders help "quickly adapt the recruits to combat." He called on them to "conduct additional training with (the mobilized) under the guidance of officers with combat experience."
The Russian minister also called on army recruitment centers not to turn away volunteers "if there are no serious reasons."
On September 21, Putin said the Defense Ministry had recommended drawing military reservists into active service as the country faced a protracted conflict in Ukraine. Putin said the measure was necessary because Russia was fighting "the entire Western military machine in Ukraine."
Russia's lower house of parliament on Monday unanimously approved laws on the annexation of four eastern Ukrainian regions, following referendums that were arranged by self-proclaimed republics.
Russia's military operation in Ukraine was launched on February 24. At the time, Putin said one of the goals of what he called a "special military operation" was to "de-Nazify" Ukraine.
Since the onset of the February conflict between the two countries, the United States and its European allies have imposed an array of sanctions on Russia and sent numerous batches of advanced weapons to Ukraine.