Pro-Russian separatist leader Alexander Zakharchenko Monday announced plans to recruit 100,000 men, as fighting with Ukrainian forces intensifies.

The separatists were trying to capture the key town of Debaltseve, while central areas of rebel-held Donetsk have been hit by artillery fire, BBC reported.

Dozens of civilians were killed on both sides of the front line during the weekend.

"Mobilisation will start in 11 days' time," Zakharchenko said.

Hundreds of civilians have been moved out of Debaltseve amid reports that the separatists have reached the outskirts of the town.

Attempts to negotiate a ceasefire failed Saturday in the Belarusian capital Minsk when rebel representatives did not turn up.