Russian and Ukrainian forces exchanged artillery fire at the front line in Ukraine on Friday, even after Moscow said it had ordered its troops to stop shooting for a unilateral truce that was firmly rejected by Kyiv.

President Vladimir Putin ordered the 36-hour cease-fire from midday on Friday to observe Russian Orthodox Christmas. Ukraine has said it has no intention to stop fighting, rejecting the purported truce as a stunt by Moscow to buy time to reinforce troops that have taken heavy losses this week.

"What cease-fire? Can you hear?" said a Ukrainian soldier, using the nom de guerre Vyshnya, as an explosion rang out in the distance at the front line near Kreminna in eastern Ukraine. "What do they want to achieve if they keep on shooting? We know, we have learnt not to trust them."