Dozens of Ukrainians were feared dead Sunday after a Russian bomb leveled a school sheltering about 90 people in eastern Ukraine.

The governor of the disputed Luhansk province where intense fighting has raged for weeks between Russian and Ukrainian forces said 30 people were rescued at the site in Bilohorivka but that the others in the school probably did not survive.

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

The latest shelling in the Donbas region came as Russia relentlessly pushed to show some battleground success in eastern Ukraine ahead of its Victory Day holiday on Monday commemorating its defeat of Nazi Germany in the European theater of World War II.

Linda Thomas-Greenfield, the U.S. ambassador to the United Nations, told CNN’s “State of the Union” show that Russia has “nothing to celebrate” with its invasion of Ukraine and has “only succeeded in isolating itself” in the world community. 

Meanwhile, Canadian Prime Minister Justin Trudeau made a surprise visit to Kyiv to meet with Ukrainian President Volodymyr Zelenskyy and then reopened the Canadian embassy in the embattled capital. 

Top U.S. diplomats, including acting Ambassador Kristina Kvien, also returned to Kyiv as the United States prepares to soon reopen its embassy there. 

While still launching missile attacks throughout Ukraine, Moscow has in recent weeks concentrated its offensive in the Donbas after failing to topple the Ukrainian government and capture  Kyiv. Russian forces control much of the eastern port city of Mariupol, except for a sprawling steel mill where as many as 2,000 Ukrainian fighters are still believed to be holding out and refusing to surrender.  

All the remaining women, children and older civilians who had been sheltering with Ukrainian fighters in the Azovstal plant were evacuated Saturday.

The Ukrainian government is trying to enlist international relief organizations to extricate wounded fighters and medics from the steel plant, but President Volodymyr Zelenskyy acknowledged the difficulty during his nightly address on Saturday.

“We are not losing hope; we are not stopping,” he said. “Every day we are looking for some diplomatic option that might work.”

G-7 pledges

Zelenskyy on Sunday met virtually with U.S. President Joe Biden and other Group of Seven leaders from Britain, Canada, France, Italy, Japan and Germany, who together head some of the world’s largest economies. The grouping has pledged billions of dollars in military aid to Ukraine.

Later, the White House said that Russian President Vladimir Putin “has failed in his initial military objective to dominate Ukraine — but he has succeeded in making Russia a global pariah.” 

“Today, the United States, the European Union and G7 committed to ratchet up these costs” by imposing further sanctions targeting Russian state-controlled media, cutting off Russian oil exports to Europe and further curbing Russian trade to other countries. 

In a Saturday address, Zelenskyy decried Russia’s bombing of a museum in the Kharkiv region dedicated to 18th century philosopher and poet Hryhorii Skovoroda.

Zelenskyy said Skovoroda was a man who “taught people what a true Christian attitude to life is and how a person can get to know himself.”

Zelenskyy said, “Well, it seems that this is a terrible danger for modern Russia — museums, the Christian attitude to life and people’s self-knowledge.”

He said Russia has destroyed nearly 200 Ukrainian cultural sites.

“Today, the invaders launched a missile strike at Odesa. At a city where almost every street has something memorable, something historical,” Zelenskyy said.

Russia’s invasion of Ukraine “should remind every state and every nation that it is impossible to defeat evil once and for all,” Zelenskyy said.

The United Nations, which is leading the civilian rescue effort at the Mariupol steel plant, along with the International Red Cross, is not confirming that the operation has ended.

While under heavy bombardment at the steel plant, fighters and civilians have been trapped for weeks in deep bunkers and tunnels that crisscross the site, with little food, water or medicine.

Russian forces backed by tanks and artillery tried again Saturday to storm Azovstal, Ukraine’s military command said, part of an assault to dislodge the last Ukrainian defenders in the strategic port city on the north coast of the Sea of Azov.

Mariupol has been left in ruins by weeks of Russian bombardment, and the steel mill has been largely destroyed.

Evidence of possible war crimes 

The World Health Organization is gathering evidence for a possible war crimes investigation. The agency said Saturday it has documented Russian attacks on health care facilities in Ukraine.

The Reuters news agency reported that WHO Emergencies Director Mike Ryan, on an unannounced visit to Ukraine with WHO chief Tedros Adhanom Ghebreyesus, told reporters of the explicit responsibility of warring parties to avoid attacking health facilities, yet the WHO had documented 200 attacks on hospitals and clinics.

“Intentional attacks on health care facilities are a breach of international humanitarian law and as such — based on investigation and attribution of the attack — represent war crimes in any situation,” Ryan said.

“We continue to document and bear witness to these attacks … and we trust that the U.N. system and the International Criminal Court and others will take the necessary investigations in order to assess the criminal intent behind these attacks,” Ryan said.

Russia has denied previous accusations by Ukraine and Western nations of possible war crimes and of targeting civilians in the war.   

Russia’s most senior lawmaker Saturday accused Washington of coordinating military operations in Ukraine, which he said amounted to direct U.S. involvement in military action against Russia.   

“Washington is essentially coordinating and developing military operations, thereby directly participating in military actions against our country,” Vyacheslav Volodin wrote on his Telegram channel.   

Reuters reports that Russian President Vladimir Putin will send a “doomsday” message to the West on the Monday holiday, but a Russian Foreign Affairs Ministry spokesman said Friday that Russia has no intention of deploying tactical nuclear weapons to Ukraine.   

“Russia firmly abides by the principle that there can be no victors in a nuclear war, and it must not be unleashed,” Alexei Zaitsev said.   

Biden’s surprise visit to Ukraine 

U.S. first lady Jill Biden was in Slovakia Sunday and later made a surprise trip into Ukraine, where she met with Ukrainian first lady OIena Zelenska and visited with schoolchildren. 

In Slovakia, Biden visited a refugee center for Ukrainians housed in a bus station. The first lady had a long conversation with Viktoце Kutocha and her 7-year-old daughter, Yulie. Viktoце Kutocha talked about leaving Ukraine, and how “cruel” the Russian attacks were.   

Later, at a school, Biden met with mothers and their children in a Mother’s Day activity.    

Biden traveled to eastern Europe to show support for U.S. troops and Ukraine.  

Some information for this story came from The Associated Press, Agence France-Presse and Reuters.