If the occupying Russian forces manage to capture the steel plant, they will take full control of the southern Ukrainian city.
But local authorities say Mariupol is in ruins, with around 90 percent of its buildings destroyed during the war.
Why are the Russians so focused on capturing Mariupol?
Polish Radio’s Wojciech Cegielski spoke to Olga Tokariuk, a Ukrainian journalist and fellow at the American think tank CEPA.
Click on the audio player above to listen.