AT LEAST 19 people, including 13 Ukrainian troops, have been killed in fighting with anti-fascist fighters in the east of the country over the last 24 hours, Kiev officials and rebels said today.

At least 20 Ukrainian troops were also wounded, said Ukrainian defence official Volodymyr Poliovyi, as the separatists advanced their offensive around key transport hub Debaltseve the day after truce talks collapsed.

Six civilians died in fighting in the region of Donetsk and around Lugansk.

The latest casualties followed the collapse of peace talks in Minsk on Saturday which had been aimed at thrashing out a ceasefire agreement to halt fighting that has killed more than 5,100 people since April 2014.

Outgoing heavy-calibre fire boomed incessantly, shaking the ground and rattling windows around the besieged town.

Residents of Debaltseve mustered at the town hall on Saturday to be evacuated.

The government-held town has been without power, water and gas for at least 10 days, prompting many to flee.

But leaving Debaltseve carries its own risks because of the encroachment of separatist forces on all sides.

Fighting inched toward Debaltseve this week when rebels burst through government lines to occupy part of the town of Vuhlehirsk.

Ukrainian troops were overrun on Thursday and were forced to retreat to Debaltseve on foot.

The United Nations has voiced concern about the deteriorating situation in Debaltseve.

UN humanitarian co-ordinator Neal Walker has called for an immediate truce to allow humanitarian assistance and the evacuation of civilians.