Russian occupiers have prepared 1,800 tanks, 3,950 armoured vehicles, 2,700 artillery systems, 810 multiple-rocket-launch systems, 400 fighter jets, and 300 helicopters ready for a new offensive operation in Ukraine.   Estimates of Russia’s presence in Ukraine are significantly higher than the invading force that Russian President Vladimir Putin used to invade the country last February — and this time, they are highly concentrated in eastern Ukraine. and Western officials now estimate that about 200,000 Russian troops have been killed or wounded in battle