On Wednesday, Moscow issued another call for the city's defenders to surrender. But that ultimatum passed and Ukrainian forces have stood firm, holing up in the sprawling Azovstal steel plant — also a refuge for up to 2,000 civilians
Russian/ pro-Russian armour gathers in eastern Mariupol for an assault on the Azovstal plant where fierce fighting continues. The battle between Russian / Pro Russian forces and the defending Ukrainian forces led by the Azov battalion continues in the port city of Mariupol. (Credit: Maximilian Clarke/SOPA Images/LightRocket via Getty Images)