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Russian forces also bombed a school building where civilians were evacuated.
The United Nations says one in four Ukrainians has fled amid Russia's air strikes and bombings with hypersonic missiles.
Reporter Ki-tae Kim reports.
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A building in Mariupol, a port city in southeastern Ukraine, has been tanned.
The building was completely destroyed by the bombardment, revealing its interior.
People who have left the building are evacuating one after another.
Mariupol city council said the bombed building was a school and about 400 residents had been evacuated.
Many of them are said to have been left under the rubble of the destroyed buildings, unable to escape.
The Russian army, which has been besieging Mariupol for over two weeks, continues to bombard civilians indiscriminately.
City officials say more than 2,500 civilians have died so far in Mariupol alone.
It is estimated that 1,200 people are still under the rubble at the theater shelter in Mariupol, which was bombed on the 16th.
The United Nations says 10 million people, about a quarter of Ukraine's population, have fled their homes after Russia's invasion of Ukraine, leaving more than 900 civilians dead.
In particular, more than 1.5 million of the refugees who have fled abroad are children, and they are concerned that they are at increased risk of being trafficked.