Rescue crews have begun pulling survivors out of the wreckage of a theater in the besieged Ukrainian city of Mariupol after it was hit by a massive explosion on Wednesday. The theater was being used as a shelter by hundreds of civilians who have endured more than two weeks of near-constant shelling by Russian forces, with no water, heat or electricity and dwindling food supplies. Satellite images clearly show the word “children” written in large letters on the ground on two sides of the theater. Another blast in Mariupol hit a swimming pool where pregnant women and young children had gathered. Elsewhere, Russian forces have been accused of killing at least 10 people standing in line for bread in the northeastern city of Chernihiv. Russia has denied responsibility for the attacks on civilians.

The United Nations Development Program on Wednesday estimated Russia’s assault has already caused over $100 billion in damage to Ukraine’s infrastructure.