Russia on Tuesday began large-scale nuclear forces drills involving tens of thousands of troops, missile systems, aircraft, ships, and submarines.

The exercises included simulated launches of nuclear-capable ballistic and cruise missiles and focused on preparing for the use of nuclear forces under perceived threats.

Officials said the drills also involved coordination with Belarus, which hosts Russian nuclear weapons, including advanced missile systems.

The exercises come amid intensified Ukrainian drone attacks on Russian territory, including strikes near Moscow that caused casualties and damage, NBC News has reported.

The maneuvers also followed recent nuclear rhetoric and policy signals from President Vladimir Putin, reinforcing Russia’s emphasis on deterrence during the ongoing war in Ukraine.