President Vladimir Putin has ordered the Russian military to hold nuclear weapons drills involving the navy and troops based near Ukraine, the defence ministry said Monday.

Putin has upped his nuclear rhetoric since the Ukraine conflict began, warning in his address to the nation in February there was a "real" risk of nuclear war.

"During the exercise, a set of measures will be taken to practice the preparation and use of non-strategic nuclear weapons," the defence ministry said.

Non-strategic nuclear weapons, also known as tactical nuclear weapons, are designed for use on the battlefield and can be delivered via missiles.

The ministry said the exercises would take place "in the near future" and were aimed at ensuring Russia's territorial integrity in the face of "threats by certain Western officials".

Aircraft and naval forces will take part, as well as troops from the Southern Military District, which borders Ukraine and includes the occupied Ukrainian territories, it said.

Western officials have become increasingly alarmed by the Kremlin's nuclear rhetoric during the offensive in Ukraine, with Putin frequently invoking Russia's nuclear doctrine.

Last year Russia ditched its ratification of the Comprehensive Nuclear Test Ban Treaty and pulled out of a key arms reduction agreement with the United States.