Russian claim of killing 600 Ukrainian soldiers rejected by Kiev as 'propaganda'
But rejecting the claim, Serhiy Cherevaty, a spokesman for the Ukrainian army, told the BBC on Sunday night that "this is another piece of Russian propaganda".
In a statement, the Russian Defence Ministry said more than 1,300 Ukrainian troops were housed in two buildings during the attack on Sunday.
Moscow is however, yet to offer any proof of its claim about the Kramatorsk deaths.
Besides Kramatorsk, there was further shelling in various parts of Ukraine overnight after the end of what Russian President Vladimir Putin said was a 36-hour ceasefire so Orthodox Christians could celebrate Christmas, reports the BBC.
Ukrainian officials said at least one person was killed in the Kharkiv region, while explosions were also reported in the southern cities of Zaporizhzhia and Melitopol.