Pro-Russian rebels in east Ukraine said Monday they will only start pulling back weapons from the frontline under a peace deal once there is a "full ceasefire".

"In accordance with the Minsk agreement, the withdrawal of military hardware can only happen under certain conditions and one of them is a full ceasefire," Eduard Basurin, a spokesman for the defence ministry of the self-proclaimed Donetsk People's Republic was quoted as saying by the rebels' official news agency.

Under a peace plan inked by the rebels and Kiev both sides were meant to start withdrawing heavy weaponry from the frontline no later than two days after the start of a truce that was meant to come into effect from 2200 GMT Saturday.

However fighting still persists around the key government-held town of Debaltseve and both sides accuse each other of continuing firing.

"If the Ukrainian army does not stop shooting and violating the Minsk agreement then the forces of the Donetsk People's Republic will not withdraw their arms," Basurin said.

The last-ditch peace deal signed in Minsk afer tortuous talks between the leaders of Ukraine, Russia, France and Germany was seen as the best hope of ending 10 months of conflict that has cost over 5,480 lives.

Ukrainian military spokesman Vladyslav Seleznyov told AFP that there was "no question" at the moment of Ukraine withdrawing its heavy arms to create a buffer zone that was intended to stretch up to 140 kilometres (87 miles).