CHICAGO (NewsNation Now) — UNICEF says that about 500,000 children have been forced to flee their homes in Ukraine over the past week due to Russia’s invasion, calling the exodus “unprecedented in scale and speed.”

“If the violence (doesn’t) stop, many, many more children will be forced to flee their country in a very short space of time,” James Elder, a UNICEF Ukraine spokesperson, said Friday. “And we fear many more will be killed.”

As the conflict enters the third week, millions of children are caught in the violence, intensifying their risk and vulnerability to being injured or killed when weapons and explosives are used in populated areas.

“The use of explosive weapons in cities could quickly turn this crisis into a catastrophe for Ukraine’s children,” said Afshan Khan, UNICEF’s Regional Director for Europe and Central Asia. “There are no armed operations of this scale that do not result in children being harmed. The consequences will be tragic.”

Hundreds of thousands of people, including children, have been displaced, fleeing Ukraine’s war-struck capital of Kyiv.

“Families coming in who have been sleeping in bunkers. Then it’s just fathers farewelling sons. Husbands and wives ripped apart from each other. Train station, the bus station, you cannot turn around without seeing tears,” Elder said.

Sheltering in basements, subway stations, bomb shelters, some children are all alone, separated from their families and parents. The United Nations Children’s Fund is one of the relief groups on the ground helping.

Elder said UNICEF is sending large amounts of humanitarian supplies to Ukraine to help those in need and providing emergency training to pediatricians being sent to the region.

“They’re preparing for a mass casualty of children,” he said, adding that the training included a triage system for treating children.

Since Feb. 27, 17 children have been killed and 30 have been injured, according to reports that the United Nations have been able to verify. The true number of child casualties is likely higher.

With no end in sight, the situation is dire for children in need of water, food, blankets and other essential items, especially for child protection specialists.

“We know what happens to children around conflict. When suddenly they lose the chance to learn in school, the new learning is what does conflict sound like,” Elder said.

The International Organization for Migration said Friday that 1.25 million people had fled Ukraine so far, including almost 80,000 third-country nationals.

UNICEF said 7.5 million children are at risk. If you’re interested in donating, www.unicefusa.org/NewsNation.