Russian Defense Minister Sergei Shoigu informed President Vladimir Putin on Monday that the country's nuclear deterrence forces have begun combat duty with reinforced staff.

Shoigu informed Putin that "the duty shifts of control units of the strategic rocket forces, the Northern and Pacific fleets, and the long-range aviation command have started to carry out the combat duty with increased capacity," Russia's RIA Novosti news agency cited the ministry as reporting.

Putin ordered the country's deterrence forces to be placed on "a special mode of combat duty" in a Sunday meeting with top defense officials.