Russia's navy has begun planned exercises involving most of its fleet in the Arctic and Pacific oceans as well as the Baltic and Caspian seas, the defence ministry said.
Russia is considered by most military analysts to have the world's third most powerful navy after those of the United States and China, and Russia has a significant ballistic-missile nuclear submarine fleet.
The Russian drills, which include 20,000 personnel and 300 ships, will test the readiness and capabilities of the navy at all levels, the ministry said.
The drills will include over 300 combat exercises including practising the use of anti-aircraft missiles, artillery, anti-submarine weapons and "passive interference", it added.
"Units and formations of the Russian Navy have begun conducting planned exercises in the operational zones of the Northern, Pacific and Baltic Fleets, as well as in the area of responsibility of the Caspian Flotilla," the ministry said.
"The main purpose of the exercises is to check the actions of the military authorities of the navy at all levels, as well as the readiness of the crews of ships, units of naval aviation and coastal troops of the Russian navy to perform tasks."
About 300 surface ships and boats, submarines and support vessels, some 50 aircraft and more than 200 units of military and special equipment will be involved in the combat training, the ministry said.
At celebrations of Russian Navy Day on Sunday, Putin warned the United States that if Washington deployed longer-range missiles in Germany then Russia would station similar missiles in striking distance of the West.
Since starting an incursion on Ukraine in February 2022, Russia has conducted numerous military exercises on its own or with other countries, including China and South Africa.
In the past two months, Russia has also conducted a series of mobile nuclear missile launcher drills and tactical nuclear weapons deployment exercises. It has also increased military training with Belarus, which borders Russia and Ukraine, conducting a series of comprehensive drills.
