A 10-year-old boy has been killed and more than 20 people wounded after a Russian missile attack on a block of flats in the centre of Kharkiv, Ukrainian officials have said. The strike on the city’s densely populated downtown area took place at 6.46am on Friday. Rescuers found the boy’s body under debris. Two Iskander missiles hit a block of flats, in what Ukraine’s president, Volodymyr Zelenskiy, called another act of “Russian terror”. The latest destruction came less than a day after a lethal strike on the small village of Hroza in Kharkiv oblast killed 52 people. It was the worst single death toll in the north-eastern region and one of the highest in Ukraine since the start of Vladimir Putin’s full-scale invasion last year. The White House condemned Thursday’s attack on a cafe and grocery store as “horrifying”, while the British prime minister, Rishi Sunak, said it “demonstrated the depths of depravity Russian forces are willing to sink to”, according to a Downing Street spokesperson. In a briefing before the death toll increased, the White House press secretary, Karine Jean-Pierre, said: “Let’s stop and think about what we’re seeing: 49 innocent people who were killed by a Russian airstrike while they were shopping for food at a supermarket. That’s what they were doing. “Can you imagine just walking to the grocery store with your kids, trying to figure out what is it that you’re going to make for dinner, and you see an explosion happen where bodies are everywhere? And it’s horrifying. “This is why we’re doing everything that we can to help Ukraine, to help the brave people of Ukraine to fight for their freedom … to fight for their democracy.” The UN’s high commissioner for human rights, Volker Türk, said he would investigate. A field team would go to Hroza to talk to survivors and collect information. “The commissioner is profoundly shocked and condemns these killings,” an Office of the United Nations high commissioner for human rights (OHCHR) spokesperson said in Geneva. According to Ukraine’s state emergency service, 26 civilians were wounded in the strike on Kharkiv on Friday, with 10 taken to hospital. Rescue workers removed rubble from the third storey of the block as fires burned in the square below. The blast blew out windows and damaged neighbouring balconies. “The murdered child is a boy. He was 10 years old. My condolences to his family and friends,” Zelenskiy posted on Telegram. He added: “The rescue operation is ongoing. I thank all our soldiers who, despite everything, are moving forward, destroying the occupiers and bringing the return of justice to Ukraine closer. Our resilience, our movement and the daily casualties of the occupiers are what must be the answer to Russian terror.” In Hroza, large piles of bricks, shattered metal and building materials remained where the cafe and shop were hit at lunchtime on Thursday. The village has a population of just 330 people. Sixty had been attending a memorial service for a local fallen soldier, said the interior minister, Ihor Klymenko, adding that every family in the village had been affected by the attack. “From every family, from every household, there were people present at this commemoration. This is a terrible tragedy,” Klymenko told Ukrainian television. The German foreign minister, Annalena Baerbock, wrote on X, formerly Twitter: “As long as bombs rain down on supermarkets and cafes, we do everything for Ukraine to protect itself from Putin’s missile terror”. Earlier on Thursday, at a meeting of European leaders in Granada, Spain, Zelenskiy and the German chancellor, Olaf Scholz, announced that Berlin was working on supplying Kyiv with a new Patriot air-defence system. Josep Borrell, the EU’s chief diplomat, said of the attack: “Intentional attacks against civilians are war crimes. Russia’s leadership, all commanders, perpetrators and accomplices of these atrocities will be held to account. There will be no impunity for war crimes.” Zelenskiy called the Hroza attack “no blind strike”. 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.” One resident, Volodymyr Mukhovaty, 70, told Agence France-Presse: “My son was just found without a head, without arms, without legs, without anything. They recognised him from his documents.” His wife and daughter-in-law were also attending the wake and although he said he had “little hope” of finding them alive, he watched rescue workers from a distance. “I lived with my wife for 48 years,” he said. “I will not last long alone.” Denise Brown, Ukraine coordinator for the UN Office for the coordination of humanitarian affairs (OCHA), called the attack “absolutely horrifying” and said: “Intentionally directing an attack against civilians or civilian objects is a war crime.” Zelenskiy, in his nightly video address, delivered while attending the summit of the European Political Community in Spain, said: “A deliberate missile strike on a village in Kharkiv region on an ordinary store and cafe. Russian troops could not have been unaware of where they were hitting. This was no blind strike.” Moscow did not immediately comment on the events in Hroza. It denies deliberately targeting civilians, but many have been killed in attacks that have hit residential areas as well as energy, defence, port, grain and other facilities. Hroza is more than 30km (19 miles) from the frontline town of Kupiansk, in an area where Russian forces have been pushing to recapture territory they lost to Ukrainian troops last year. Zelenskiy said a six-year-old boy was among the dead, and regional officials said families had remained in the village despite a wartime order to evacuate. Klymenko said initial evidence showed an Iskander missile had been used. He said people had been clearly targeted and that Ukrainian security services had launched an investigation into the matter. Rescue workers made their way through mounds of debris and laid out bodies in a field next to a children’s playground. Some were placed in white body bags and taken away. Others were barely covered by carpets or other materials. “It’s difficult to talk about this, but we only found bits and pieces and remains of the bodies,” said the regional police investigator Serhiy Bolvinov. “We’ll use DNA laboratories to identify the bodies.” The missile hit during the service marking the reburial of the soldier who had died in action elsewhere. “There were only civilians. The boy was from this village. When he died, we were under occupation. The [family] decided to rebury him, to bring him home,” said one resident, Oleksandr Mukhovatyi. “Then this happened. Someone betrayed us. The attack was precise, it all landed in the coffee shop.” Mukhovatyi said his mother, brother and sister-in-law were among the dead. Prosecutors told the public broadcaster Suspilne that the son of the soldier being reburied – also a soldier – had been killed too. Rustem Umerov, the defence minister, said: “The terrorists deliberately carried out the attack during lunchtime, to ensure a maximum number of casualties. There were no military targets there. This is a heinous crime intended to scare Ukrainians.”