Volodymyr Zelenskiy has accused Russia of “brutal” and “genocidal aggression” after a missile hit a cafe during a wake service in a village in the Kharkiv region, killing at least 51 people including a six-year-old boy. Volodymyr Zelenskiy Ukraine’s president said rescuers were searching for survivors at the scene. The attack took place at 1.15pm in the village of Hroza, in the Kupiansky district of the north-eastern Kharkiv province. He described it on Telegram as “a demonstrably brutal Russian crime – a rocket attack on an ordinary grocery store, a completely deliberate act of terrorism. My condolences to all those who have lost loved ones.” Ukraine’s minister of internal affairs, Ihor Klymenko, said on Telegram the death toll stood at 51 and that “debris analysis is ongoing”. Klymenko added that victims had gathered to remember a deceased villager in Hroza, which has a population of 330. Ukrainian forces recaptured the village last year as part of a sweeping counteroffensive in Kharkiv oblast. It is situated more than 25 miles (40km) from the frontline, where there has been fierce fighting around the town of Kupiansk and in nearby forests. Video footage from Hroza showed bodies laid out on the grass and rescue workers picking over a landscape of rubble. The cafe had been completely obliterated. According to preliminary findings, the Russians targeted the cafe with an Iskander ballistic missile, Klymenko said. About 60 people were in the cafe at the time, he added. They had gathered for a memorial lunch for a villager who had recently died, Klymenko told Ukrainian TV. About 10% of the village’s population of 500 were killed in the attack. It was the worst ever single death toll in Kharkiv province, which has been repeatedly bombarded since last year’s full-scale invasion, officials said. Zelenskiy said the latest strike showed “Russian terror must be stopped. All those who help Russia circumvent sanctions are criminals. Everyone who supports Russia until now supports evil.” He added: “Russia needs this and similar terrorist attacks for only one thing: to make its genocidal aggression the new norm for the whole world. And I thank every leader, every nation, that supports us in protecting life.” The Ukrainian government was talking to European leaders about further boosting the country’s air defences, said Zelenskiy, who is attending an international conference in Spain. “We will answer the terrorists. Absolutely fair. And powerfully,” he said. Mykhailo Podolyak, an adviser to Zelenskiy, said the strike was an “insidious Russian attack that has no military logic”. He said the “whole civilised world” had to defeat “Putin’s evil”, adding: “This is not just a metaphor or figure of speech.” Rustem Umerov, Ukraine’s new defence minister, said the attack was “cruel and deliberate”. He said he was discussing with allies “more air defence systems to protect our country from terror”. Moscow has not yet commented on the strike. Throughout the 19-month war, Russian armed forces have repeatedly targeted civilians and civilian objects in Ukraine. A strike last month on a city in eastern Ukraine that killed at least 17 civilians may have been caused by an errant missile fired by Ukraine, in what appeared to be a tragic mishap. Hours after the strike, Vladimir Putin ramped up his nuclear rhetoric, saying Russia had successfully tested the nuclear-powered, nuclear-capable Burevestnik strategic cruise missile and had almost completed work on its nuclear-capable Sarmat intercontinental ballistic missile system. “In the event of an attack on Russia, no one has any chance of survival,” the Russian president said, in a speech at the annual Valdai Discussion Club, a Kremlin-affiliated research institute in Sochi. He said he was “not sure if we need to carry out nuclear tests or not”, adding that Moscow could “theoretically revoke ratification” of the international nuclear test ban treaty. Putin also repeated some of his grievances with the west in the speech, claiming that “western influence over the world is a giant Ponzi scheme”.