Scores of Ukrainians were feared dead Sunday after a Russian bomb flattened a school where about 90 people were taking shelter in the basement, while Ukrainian fighters held out inside Mariupol’s steel plant as Moscow’s forces apparently raced to capture the city ahead of Russia’s Victory Day holiday.

Emergency crews found two bodies and rescued 30 people at the school in the village of Bilohorivka, after Saturday’s bombing, according to the governor of Luhansk province, part of the eastern industrial heartland known as the Donbas.