Russia has shifted thousands of regular forces to staging stations closer to Ukraine as tensions between Moscow and the West grow. Following that, Moscow demanded immediate security assurances from the West, ostensibly to protect Ukraine and other neighboring nations from being used as launching sites for attacks on Russia. Russia has been charged by the West and Ukraine with planning a new attack on its southern neighbor as early as next month, which Moscow opposes. In 2014, Russia seized the Crimean Peninsula from Ukraine and supported pro-Russian rebels who captured a section of eastern Ukraine’s economic Donbas area and are now fighting Ukrainian government troops there.
Source: https://www.newshub.co.nz/home/world/2021/12/russian-mercenaries-deploy-into-ukraine-receive-special-training-in-sabotaging-stability.html