Russia and Ukraine on Friday accused each other of carrying out the shelling of a prison in a separatist eastern region that reportedly killed dozens of Ukrainian prisoners of war who were captured during the fighting for Mariupol.
"A missile strike from the U.S.-made multiple launch rocket system (HIMARS) was carried out on a pre-trial detention center in the area of the settlement of Olenivka, where Ukrainian military prisoners of war, including fighters from the Azov battalion, are being held," Russia's Defense Ministry said in its daily briefing.
As a result of the strike, "40 Ukrainian prisoners of war were killed and 75 wounded," and eight prison staff were also injured, it added.
Daniil Bezsonov, a spokesperson for the Russia-backed separatists in the Donetsk region, said that at least 40 Ukrainian prisoners of war were killed and scores were injured Friday when Ukrainian shelling hit a prison in the town of Olenivka.
The Ukrainian military denied any rocket or artillery strikes on Olenivka, insisting that it wasn't shelling civilian areas and only strikes Russian military targets.
It accused the Russian forces of deliberately shelling the prison in Olenivka in order to accuse Ukraine of war crimes and also to cover up torture and executions there.
The statement denounced the Russian claims as part of an "information war to accuse the Ukrainian armed forces of shelling civilian infrastructure and the population to cover up their own treacherous action."
The Ukrainian troops were taken prisoner after the fierce fighting for Ukraine's Azov Sea port of Mariupol, where they holed up at the giant Azovstal steel mill for months.
The Azov Regiment and other Ukrainian units defended the steel mill for nearly three months, clinging to its underground maze of tunnels. They surrendered in May under relentless Russian attacks from the ground, sea and air.
Scores of Ukrainian soldiers were then taken to prisons in Russian-controlled areas such as the Donetsk region, a breakaway area in eastern Ukraine that is run by Russia-backed separatist authorities.
Meanwhile, Russian strikes on the heavily bombed Ukrainian city of Mykolaiv near the country's southern front line killed four people and wounded seven more on Friday.
"Today, they shot at another area near a public transport stop. According to the latest information, four people are dead and seven are injured," the regional governor, Vitaliy Kim, said in a statement on social media.
Ukrainian officials also said Russian forces shelled the country's second-largest city, Kharkiv.
City mayor Ihor Terekhov said a central part of the northeastern city was hit, including a two-story building and a higher education institution. Terekhov said the strike occurred just after 4 a.m. on Friday.
"The State Emergency Service is already working - they are sorting out the rubble, looking for people under them," Terekhov said in a Telegram update.