Ukraine lost 179 troops in the one-month battle with pro-Russian rebels that ended in defeat over the key eastern town of Debaltseve, Yuri Biryukov, an advisor to Ukraine's president said on his Facebook page.
If that figure is confirmed, it would represent one of the bloodiest losses suffered by the Ukrainian side in the 10-month conflict.
Kiev has officially given a toll of 13 soldiers killed on Tuesday and Wednesday, when Debaltseve was overrun by the pro-Russian separatists in defiance of a UN-backed truce.