Russia on Monday declared a unilateral ceasefire with Ukraine between May 8-9, when Moscow marks its annual World War II Victory Day commemorations, and threatened a “massive missile strike” on Kyiv if Ukraine violated it. Ukraine responded by declaring a truce of its own between May 5-6, saying it was “not serious” to expect it to observe a ceasefire during a Russian military holiday. The quarrelling between the two sides comes with a lull in US-led diplomatic efforts to end the war, as Washing