Russia began a large-scale three-day nuclear military exercise Tuesday that will include simulated launches of ballistic and cruise missiles, according to the Russian Defense Ministry.

The drills are designed to rehearse “the preparation and use of nuclear forces in the event of aggression,” the ministry said.

Russian officials stated that approximately 64,000 personnel and 7,800 pieces of military equipment are participating in the exercises.

The operation will involve units from Russia’s strategic rocket forces, the Northern Fleet, the Pacific Fleet and long-range aviation forces, along with military units from the Leningrad Military District and Central Military District.

According to the ministry, the exercises include more than 200 missile launchers, 140 aircraft, 73 surface vessels and 13 submarines, including eight strategic nuclear submarines.

The drills will also feature training exercises involving Russian tactical nuclear weapons stationed in Belarus, the ministry added.

The exercises come amid heightened tensions between Russia and Western countries over ongoing regional and global security concerns.