Some survivors have emerged on Thursday from the rubble of a theater in Ukraine that was bombed by Russia on Wednesday despite being marked by the word "children."

The theater in Mariupol was hit while hundreds of people were huddled in its bomb shelter. Satellite images show that the theater had "children" written on both sides of the building.

"After an awful night of not knowing, we finally have good news from Mariupol on the morning of the 22nd day of the war. The bomb shelter [the theater] was able to hold. The rubble is beginning to be cleared. People are coming out alive," Sergei Taruta, the former Donetsk region head, said Thursday on Facebook, CNN reported.

Russia denies responsibility for the attack, while Ukrainian officials have called it a war crime.

"The building is now fully ruined," Dmytro Kuleba, Ukraine's foreign minister, said. "Stop Russian war criminals!"

It is still unclear how many people inside the theater survived the attack.

"You've probably already heard that this theater which was struck by missiles, a theater where 1,200 women and children were hiding," Ukraine's minister of defense, Oleksii Reznikov, told the European Parliament on Thursday, according to CNN.

"And you can see from the maps, from the drones that around this theater, big letters of 'children' were written so that the pilot of the plane which was throwing the bombs could see 'children,' and still, in spite of that, this monster has bombed the theater," he added.