By Stefan J. Bos
People were searching for survivors beneath burning debris, as many mothers here faced a horrific Mother's Day. The regional governor announced that scores of people died in this school in the village of Bilohorivka.
Authorities say some 90 people were hiding when Russian forces dropped a bomb, causing a blaze that engulfed the building. Moscow has always denied hitting civilian targets, but witnesses tell a different story.
Rescue teams brought 30 people to safety, but the others are now feared dead.
Uniformed men were struggling as they tried to carry out rescue and recovery work between the fires in this devastated area.
The site is near the frontline in the Donbas region. Russian forces push for a military success here ahead of Russia's annual May 9Victory Day, marking the World War Two defeat of Nazi Germany.
Elsewhere diplomatic efforts are underway to rescue wounded soldiers from the besieged steel plant in Ukraine's bombed-out city of Mariupol, named after the Virgin Mary.
Russia and Ukraine claim all "remaining women, children, and elderly" were evacuated from the Azovstal steelworks on Saturday. But many Ukrainian soldiers couldn't leave the plant for weeks, with Moscow demanding their surrender.
Russia also launched several missile strikes at the southern port city of Odessa over the weekend.
Despite setbacks, Ukraine is continuing a counter-offensive near the city of Kharkiv and claims to have recaptured five villages.
As the war continued, Ukraine's President Volodymyr Zelensky was to hold talks through a video link with leaders of the Group of Seven of the world's leading economies. Among them are US President Joe Biden and British Prime Minister Boris Johnson.
European Union ambassadors were also meeting in Brussels on Sunday to discuss the sixth round of economic sanctions against Moscow. But EU member Hungary has already threatened to veto a planned European oil embargo against Russia, saying it would mean an atomic bomb on Hungary's economy, which is heavily reliant on Russian energy.