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.

After being accused of violating the last short-term truce, President Vladimir Putin says Russia will halt its war in Ukraine for three days to mark 80 years since the defeat of Nazi Germany.