Scores of Ukrainians were feared dead after a Russian bomb flattened a school where about 90 people were taking shelter in the basement.

Meanwhile 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.

“Most likely, all 60 people who remain under the rubble are now dead,” Gov. Serhiy Haidai wrote on the Telegram messaging app. Russian shelling also killed two boys, ages 11 and 14, in the nearby town of Pryvillia, he said.

As Moscow prepared to celebrate the 1945 surrender of Nazi Germany with a Victory Day military parade on Monday, a lineup of Western leaders made surprise visits to Ukraine in a show of support.

US first lady Jill Biden met with her Ukrainian counterpart, and Canadian Prime Minister Justin Trudeau raised his country’s flag at its embassy in Kyiv.

The newly appointed acting US ambassador to Ukraine, Kristina Kvien, posted a picture of herself at the American Embassy, trumpeting plans for the eventual US return to the Ukrainian capital after Moscow’s forces abandoned their effort to storm Kyiv weeks ago and began focusing on the capture of the Donbas.

Ukrainian President Volodymyr Zelenskyy and others warned in recent days that Russian attacks would only worsen in the lead-up to Victory Day, and some cities declared curfews or cautioned people against gathering in public. Russian President Vladimir Putin is believed to want to proclaim some kind of triumph in Ukraine when he addresses the troops on Red Square.

“They have nothing to celebrate tomorrow,” Linda Thomas-Greenfield, US ambassador to the United Nations, told CNN.

“They have not succeeded in defeating the Ukrainians. They have not succeeded in dividing the world or dividing Nato. And they have only succeeded in isolating themselves internationally and becoming a pariah state around the globe.”