Russia said on Sunday that, it had carried out a devastating retaliatory strike in eastern Ukraine to avenge a recent deadly attack on its troops, a claim quickly denied by Kyiv.<br />''<br />''More than 600 Ukrainian servicemen were killed by a missile strike on troops stationed in two buildings used as barracks in Kramatorsk, said a Russian Defence Ministry statement.<br />''<br />''Russia described the attack as a "retaliatory strike" following Ukraine's New Year's Eve missile salvo in the eastern Ukrainian town of Makiivka, which Moscow said killed 89 of its soldiers.<br />''<br />''Ukraine's armed forces rejected Russia's claim about the Kramatorsk attack.<br />''<br />''The Russian statement did not say when exactly the strike had taken place — only that Russian intelligence had "over the past 24 hours" located more than 1,300 Ukrainian troops in two buildings in Kramatorsk.<br />''<br />''The industrial city, in the eastern Donetsk region, has been the target of repeated Russian missile attacks.<br />''<br />''While Russia conceded 89 troops had died, the worst single reported loss from a Ukrainian strike since the war began last February, one statement from Ukraine's military claimed the losses came to more than 400.<br />''<br />''Russian President Vladimir Putin ordered a 36-hour ceasefire to allow Orthodox Christians to mark Christmas, which was celebrated Saturday in Russia and Ukraine.<br />''<br />''In his evening address on Sunday, Ukrainian President Volodymyr Zelensky denounced "Russian shelling of Kherson with incendiary ammunition right after Christmas", in the southeast.<br />