Ukraine says it was struck by a new barrage of deadly Russian air attacks as an Easter ceasefire ended and as the US pushes for a deal between Moscow and Kyiv to end the three-year-long conflict.

Ukraine's skies were pierced by the wail of sirens on Monday morning, marking the end of a brief Easter peace and the return of relentless conflict.

Dozens of explosions rocked Kursk City in the "massive attack", with Moscow reports saying a woman, 85, had died, with nine people suffering shrapnel wounds.