No evidence given. Local Donetsk media reported a completely different version of the story. The city’s regional news portal Donetskie Novosti reported that three schoolboys were playing in a school stadium and they threw a rock at an unidentified object which exploded, killing one boy and wounding the other two, citing Donetsk regional administrator chief Maksym Zhukovsky as the source. The object turned out to be an unexploded mine. https://dnews.dn.ua/news/656095, http://www.osce.org/special-monitoring-mission-to-ukraine/355221. Further debunking at Stopfake https://www.stopfake.org/en/fake-ukrainian-shelling-kills-donetsk-boy/.