The refusal of Ukraine and Western powers to recognise Moscow's control of Crimea poses a "systemic threat" for Russia and any outside attack on the region will prompt a "Judgment Day" response, former president Dmitry Medvedev said on Sunday. Russia annexed the Black Sea peninsula of Crimea from Ukraine in 2014 after a pro-Moscow president in Kyiv was toppled amid mass street protests. Moscow then also backed pro-Russian armed separatists in the Donbas region of eastern Ukraine. In the event of an attack on Crimea, Medvedev was quoted by TASS news agency as saying, "Judgment Day will come very fast...