In a speech on Friday night, the Ukrainian president said more than 50 had died in the Olenivka attack, calling it “a deliberate Russian war crime, a deliberate mass killing of Ukrainian prisoners of war”. The captured fighters – who the Russian Defense Ministry said included members of the Azov Battalion, which defended the Azovstal steel plant in Mariupol – should have been protected by safeguards provided by the United Nations and the International Committee of the Red Cross, Zelenskiy said. , who joined his secretary of state in calling on these organizations to step in and investigate. Olenivka is about 10 kilometers south of occupied Donetsk and close to the front line. Obtaining responsibility is likely to be very difficult without independent access to the site. The Red Cross said it had requested access to determine the health and condition of those in the prison at the time of the attack. “Our priority at this time is to ensure that the injured receive life-saving treatment and that the bodies of those who lost their lives are treated with dignity,” she said in a statement. Farhan Haq, deputy spokesman for the UN secretary-general, told a news conference on Friday that he did not yet have first-hand information about the attack and that “the issue of access is also a difficult point.” “We would strongly encourage … all parties on the ground to fully investigate what happened,” he said. The Russian Defense Ministry said 40 inmates were killed and 75 wounded in the attack on the prison, but accused Ukrainian forces of hitting the prison with US-made Himars rockets. Moscow describes the Azov Battalion, a former paramilitary unit with past links to far-right groups, as a neo-Nazi organization. Ukraine’s defense forces denied responsibility for the attack and said Russian artillery had targeted the prison to cover up the fact that men held there had been “tortured and murdered”. The country’s foreign minister, Dmytro Kuleba, said earlier that Russia had committed a “barbaric war crime”. Ukraine’s military intelligence service said the strike was a “deliberate act of terrorism” and its domestic security agency, the SBU, said it had intercepted phone calls pointing to Russia’s responsibility. Ukraine’s attorney general, Andriy Kostin, said he had opened a war crimes investigation into the explosion. There was no way to immediately verify either version of events. Footage broadcast on Russian television said to have come from the prison scene showed military personnel examining a building with a hole in the roof, tangled metal from bunk beds and traces of blood among personal belongings. Other images showed charred bodies and dismembered limbs. Later, Russian media published images of what they said were fragments from a US Himars missile, assembled and placed on what appeared to be a bench rather than in situ. The SBU claimed to have intercepted phone calls “in which the occupiers confirm that Russian troops are responsible for this tragedy.” The intercepted conversations indicated that the Russians may have planted explosives in the prison, the agency said in a statement. “Specifically, none of the eyewitnesses heard any rockets flying towards the penitentiary. There was no characteristic hissing and the explosions happened by themselves.” In addition, online videos showed that windows remained intact in some rooms of the facility, according to the SBU. This “indicates that the epicenter of the explosion was inside the damaged building and its walls were hit by the blast waves, protecting some of the neighboring rooms.” Ukraine’s presidential adviser Mykhailo Podolyak called for a “rigorous investigation” into the attack and urged the UN and other international organizations to condemn it. He said the Russians had moved some Ukrainian prisoners to the barracks just days before the strike, suggesting it was planned. The Russian allegations, he said, were “a classic, cynical and elaborate false flag operation” designed to discredit Ukrainian authorities. The Azov Regiment and other Ukrainian units defended the Azovstal steelworks for nearly three months, clinging to the underground maze of tunnels. They surrendered in May under relentless Russian attacks by land, sea and air. Dozens of Ukrainian soldiers were jailed in Russian-controlled areas such as Donetsk, a region in eastern Ukraine run by Russian-backed separatist authorities. Some have returned to Ukraine as part of prisoner exchanges with Russia, but the families of others have no idea if their loved ones are alive or if they will ever return home. Friday’s attack raises serious questions about where the detainees were being held, in what conditions and why they had not been moved to a safer location. It also raises questions about the condition of the dead. Under the Geneva Conventions, registered prisoners of war would not be tried for lawful participation in a conflict.