Russia on Wednesday showed what it said was footage of troops delivering nuclear warheads to mobile Iskander-M launch systems, loading them and moving them undetected to launch sites as part of a major nuclear exercise.In a statement released to state media, the Defense Ministry said its forces had practiced bringing units to “the highest levels of combat readiness for the use of nuclear weapons.”For all the latest headlines, follow our Google News channel online or via the app.The three-day exercise, which started on Tuesday and is taking place across Russia and Belarus, comes at a time when Moscow is locked in what it says is an existential struggle with the West over Ukraine and tensions with NATO and Europe over the war are running high.The Defense Ministry said on Tuesday that the drills, which involve 64,000 military personnel, over 200 missile launchers, 140 aircraft, 73 surface ships and 13 submarines, would include rehearsing launch procedures for Russian tactical nuclear weapons based in Belarus.Video of the training element showed Russian nuclear forces moving in convoy through a heavily forested area, camouflaging their vehicles, and raising a launch tube into firing position.With a range of up to 500 km (310 miles), the Iskander-M can carry both nuclear and conventional warheads.Read more: Russia announces three-day nuclear drills