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.

President Zelensky of Ukraine said the front lines had seen artillery fire and drone attacks, and that his troops were responding. Russia accused Ukraine of breaking the cease-fire.