The United States said the strikes carried out on Friday in eastern Ukraine showed that the ceasefire announced by Vladimir Putin for Orthodox Christmas was a “cynical” step.

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State Department spokesman Ned Price, recalling having already used the adjective to describe the Russian announcement the day before, told reporters on Friday: "I believe the validity of this assessment has been confirmed, given what we witnessed all day.”

“Our skepticism is justified by what we have witnessed from Russia throughout this conflict,” he added.

"Our concern is that Moscow will use any cessation of fighting to re-equip, regroup and finally re-attack with more vengeance, brutality and even lethality," he said.

Artillery duels continued Friday in Bakhmout, the epicenter of fighting in eastern Ukraine, as well as shelling elsewhere in the country.

Moscow's announcement of this unilateral 36-hour ceasefire has been denounced as a maneuver by Kyiv and its Western allies.