Russia declared on Monday 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 Kiev if Ukraine violated it.
Russian President Vladimir Putin first proposed the truce last week, during a phone call with US counterpart Donald Trump.
Ukraine said last week it would seek details from Washington about the offer.
"In accordance with a decision of the Supreme Commander-in-Chief of the Russian Armed Forces, Vladimir Putin, a ceasefire has been declared from May 8–9, 2026 ... We hope that the Ukrainian side will follow suit," the Russian defence ministry said in a post on state-backed messaging app MAX.
"If the Kiev regime attempts to implement its criminal plans to disrupt the celebration of the 81st anniversary of Victory in the Great Patriotic War, the Russian Armed Forces will launch a retaliatory, massive missile strike on the centre of Kiev."
"We warn the civilian population of Kiev and employees of foreign diplomatic missions of the need to leave the city promptly," it added.
In response, President Volodymyr Zelenskyy said Ukraine will observe its own truce with Russia between May 5-6.
"As of today, there has been no official appeal to Ukraine regarding the modality of a cessation of hostilities that is being claimed on Russian social media," Zelenskyy said in a post on X.
"In this regard, we are announcing a ceasefire regime starting at 00:00 (2100 GMT) on the night of May 5–6. In the time left until that moment, it is realistic to ensure that silence takes effect," he added.
