The cease-fire ordered unilaterally by Russian President Vladimir Putin to coincide with the start of Orthodox Christmas began Friday but was rejected by Ukraine and its allies as a cynical move designed to buy time on the battlefield and favor in the eyes of the public.

The 36-hour truce declared by Russia came into effect at midday Moscow time (4 a.m. ET) and was due to last until midnight Saturday (4 p.m. ET).

But Kyiv dismissed the suggestion of a pause in hostilities for the holiday, and the situation on the conflict's front lines was unclear. About an hour after the Russian cease-fire began, air raid sirens sounded in the capital, Kyiv.

Ukrainian officials accused Putin of using Christmas as cover to buy time for his military to regroup.

“Now they want to use Christmas as a cover to stop the advance of our guys in the (eastern) Donbas (region) for a while and bring equipment, ammunition and mobilized people closer to our positions,” President Volodmyr Zelenskyy said late Thursday.

Everyone in the world knows how the Kremlin uses lulls in the war to continue the war with new force,”