Russia's Defense Ministry declared a unilateral ceasefire in Ukraine for Friday and Saturday to mark the 81st anniversary of the defeat of Nazi Germany in World War II, but it threatened to strike back at Kyiv if it tries to disrupt the Victory Day festivities.Ukrainian President Volodymyr Zelenskyy in response said his country would observe a truce beginning at 12 a.m. on Wednesday and respond in kind to Russia's actions from that moment on. He did not put an end date on the truce.advertisementRead Full StoryThe announcements on Monday come as Russia prepares to celebrate its most important secular holiday…