Moscow has conducted an aggressive military recruitment campaign this year as it seeks to stave off an ongoing Ukrainian counteroffensive and hold territories it has captured during the conflict.

"According to the Ministry of Defence, from 1 January to 3 August... a total of more than 231,000 people have been accepted for contract service," said Medvedev, who served as president from 2008-2012.

Last September, President Vladimir Putin announced a "partial" military mobilisation -- Russia's first since World War II -- sending shock waves across the country as thousands of men were drafted into the army.

Unwilling to announce a second mobilisation drive, Moscow has instead opted for a massive PR campaign, hoping to lure Russians with financial incentives.

Authorities have not disclosed their targets but various estimates say Moscow could be trying to recruit 400,000 volunteers.

Defence Minister Sergei Shoigu said last year the size of Russia's army would be increased to 1.5 million people, as Moscow presses ahead with its offensive in Ukraine.