Moscow also declared a temporary truce over Easter, but Ukraine accused Russia's own forces of violating it thousands of times. Russia has long rejected a full ceasefire unless Ukraine accepts a list of maximalist Kremlin demands, including demilitarizing and ceding vast swathes of territory.

The Kremlin said on Monday that President Vladimir V. Putin had ordered a three-day cease-fire in Ukraine next month, the second time in two weeks that Russia’s leader has promised a temporary pause in the fighting as President Trump shows growing impatience with his refusal to stop the war.

Russian President Vladimir Putin on Monday declared a three-day ceasefire in May in the war with Ukraine to mark the 80th anniversary of the victory of the Soviet Union and its allies in World War Two.