The longtime Russian leader on Monday signed a decree boosting the number of active troops by 180,000 soldiers -- making the Russian army the second largest in the world by active troop size.

Russia has become increasingly militarised during the Kremlin's Ukraine offensive and it is the third time Putin has ordered a troop boost since launching the conflict in February 2022.

"In close cooperation between federal and regional authorities, it is necessary to solve the key task of ensuring that the armed forces are manned with prepared, trained people, prepared by personnel," Putin said during a meeting with defence officials.

"I am referring in particular to the units and compounds of permanent combat readiness of the new military districts," Putin added.

Russia restructured its military districts earlier this year -- forming the Moscow and Leningrad military districts -- in response to tensions with the West.