The European Union called Monday for full implementation of a hard-won Ukraine ceasefire, insisting that "the shooting needs to stop."

"We are now following very closely implementation of the Minsk agreement which appears to be largely holding despite a number of incidents," European Commission spokeswoman Maja Kocijancic said.

"It is imperative the ceasefire is fully implemented. A ceasefire is a ceasefire; it means the shooting needs to stop," Kocijancic said.

The leaders of France, Germany, Russia and Ukraine agreed a ceasefire deal last week in the Belarus capital Minsk to end fighting between government troops and pro-Russian rebels which has claimed more than 5,400 lives in the past year.

The ceasefire came into effect at 2200 GMT Saturday and was meant to be followed by the withdrawal of heavy weapons beginning Monday, but this looked increasingly in doubt as both sides traded accusations of bad faith and fresh attacks.

The worst breaches of the ceasefire were reported around Debaltseve, a key transport hub located between Donetsk and Lugansk, the main rebel strongholds.

AFP journalists and an OSCE monitoring team near Debaltseve observed shelling in the area.