KYIV, Ukraine (AP) — Russia launched a pre-dawn missile barrage at the Ukrainian capital Thursday, killing three people, including a 9-year-old and her mother, and damaging apartment buildings, schools and a children’s hospital, officials said. It was the highest 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 air-raid shelter, which left the group at the mercy of falling missile fragments, according to her husband. Officials ordered an investigation.

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

Ukrainian air defenses shot down all 10 missiles, but falling debris caused damage and wounded 16 people, authorities said.

Russia has kept up a steady barrage on the 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.

“Children’s Day has to be about safe childhood, summer, life,” tweeted Ukraine’s first lady, Olena Zelenska. “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 air-raid shelter that was locked, Yaroslav Riabchuk said he and his wife of 17 years, Natalia, were outside 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. He gave orders to the heads of the city’s districts to immediately check if all the shelters in Kyiv were accessible.

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

Six children were killed and 34 were wounded last month alone, the mission said.

“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.

The Ukrainian Defense Ministry cited different figures for child casualties in the war, saying at least 484 children have been killed and 992 wounded. It was not immediately possible to reconcile those numbers with the U.N. figures.

Meanwhile in Moscow, Russian President Vladimir Putin led a meeting with families via video link to mark the 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 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.

Russia has repeatedly targeted Kyiv since the start of the invasion, but attacks against the capital have intensified over the past month. While Ukraine’s air defenses have become increasingly effective at intercepting Russian drones and missiles, many Kyiv residents are anxious and tired after weeks of sleepless nights.