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.

Ukrainian President Volodymyr Zelenskyy announced his own ceasefire, saying in a statement posted on X that he has not received an official appeal from Russia about its truce.

"We believe that human life is far more valuable than any anniversary "celebration". In this regard, we are announcing a ceasefire regime starting at 00:00 on the night of May 5-6," Zelenskyy said. "In the time left until that moment, it is realistic to ensure that silence takes effect. We will act reciprocally starting from that moment."

Russian President Vladimir Putin first proposed the short-term truce last week, during a phone call with President Trump.

"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 defense ministry said in a post on state-backed messaging app MAX.

"If the Kyiv 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 center of Kyiv," it added. "We warn the civilian population of Kyiv and employees of foreign diplomatic missions of the need to leave the city promptly."

May 9 is the day on which Russia celebrates its victory over the Nazis. Due to the time difference between Russia and the Western European nations where the German surrender was cemented, the U.S. and its European allies mark the victory in Europe on May 8 every year — the day on which Adolf Hitler's forces capitulated to the Allies in 1945, ending World War II on the continent.

Last year, Putin declared a similar ceasefire in Ukraine to mark Victory Day.

In response to Russia's message on Monday, Zelenskyy said: "It is time for Russian leaders to take real steps to end their war, especially since Russia's Defense Ministry believes it cannot hold a parade in Moscow without Ukraine's goodwill."