Political map of Russia & the former Soviet Union 30 June 2014 (Donbass Rebellion): When Crimea acceded to the Russian Federation in March 2014 (Accession of Crimea to the Russian Federation), the US and its allies moved to support Ukraine by imposing sanctions on Russia. As the rift between Ukraine and Russia widened, pro-Russian unrest broke out across southern and eastern Ukraine (2014 pro-Russian unrest in Ukraine). The movement was strongest in the southeastern Donbass region where separatist groups took power in Donetsk and Luhansk (Donbass War).