Authorities in the rebel stronghold of Donetsk in eastern Ukraine say at least 5 people have been killed and 13 injured by artillery fire in the past day.

The city hall said in a statement early on Tuesday that artillery fire has damaged homes in four districts of the city.

Hostilities between pro-Russian separatists and Ukrainian government troops resumed in January after a month of relative calm. Their main offensive is now directed at Debaltseve, a railway junction once populated by 25,000 people that lies between the rebel-held cities of Luhansk and Donetsk.

Recent talks to settle the conflicts broke down on Friday with both sides blaming each other for derailing the peace process to end a conflict that has killed more 5,100 people.