KYIV, Ukraine (AP) — Russia launched a pre-dawn missile barrage on Ukraine’s capital Thursday, killing three people including a nine-year-old and her mother, officials said, and damaging apartment buildings, schools and a children’s hospital. It was the highest casualty toll from a single attack on Kyiv over the past month.

A 33-year-old woman died as she and others waited to enter a locked Kyiv air raid shelter, leaving her and others at the mercy of falling missile fragments, according to her husband. Officials ordered an investigation into what happened.

The latest Russian attack, using what Ukrainian officials said were short-range Iskander ground-launched missiles, coincided with events scheduled in Kyiv to celebrate International Children’s Day. Those events were canceled.

Ukrainian air defenses shot down all 10 cruise and ballistic missiles launched by the Kremlin’s forces, but falling debris caused damage and casualties on the ground, wounding 16 people, according to authorities.

Russia has kept up a steady barrage on the Ukrainian capital and other parts of the country in recent weeks as Kyiv readies what it says is a counteroffensive to push back Moscow’s troops, 15 months after their full-scale invasion. Kyiv was the target of drone and missile attacks on 17 days last month.

Ukraine’s first lady, Olena Zelenska, said one child was in hospital after the attack.

“Children’s Day has to be about safe childhood, summer, life,” she tweeted. “But today it is about new crimes of (Russia) against children.”

Ukrainian Foreign Minister Dmytro Kuleba tweeted that the dead included a 9-year-old girl, her mother and another woman.

At the Kyiv air raid shelter that was locked, Yaroslav Riabchuk said he and his wife of 17 years, Natalia, were outside with others when he ran around the back of the building to summon the guard in charge.

“I ran, but then an explosion happened,” Riabchuk said. “Shattered glass started falling, and I knew I had to run back. When I returned, it was over. There was a lot of blood, women, children.”

Mayor Vitali Klitschko said authorities were investigating what happened. He gave orders to the heads of the city’s districts to immediately check if all the shelters in Kyiv are accessible.

UN human rights monitors said six children were killed and 34 were wounded last month alone.

Since February 2022, at least 525 children have been killed and at least 1,047 have been injured, according to the UN’s Human Rights Monitoring Mission in Ukraine.

“Sadly, as the world marks International Children’s Day, there is little to celebrate in Ukraine where civilians, including children, continue to pay a heavy price” said Matilda Bogner, the mission’s chief.

In Moscow, meanwhile, Russian President Vladimir Putin was chairing a meeting with families via video link to mark International Children’s Day.

Putin met with families that have many children and vowed to maintain state subsidies and other measures to support them. When one of the participants in the meeting voiced confidence that Russia would be victorious in what the Kremlin calls the “special military operation” in Ukraine, Putin noted that “it will be so.”

“There is no doubt about it, because we are protecting our land, our people and our values,” he said.

The Ukrainian Ministry of Defense cited different figures for child casualties in the war, saying at least 484 children have been killed and 992 injured. It was not immediately possible to reconcile the differences with the UN figures.