A video released by Ukraine’s Azov regiment appears to show civilians, many of them children, sheltering alongside soldiers, inside Azovstal steel plant in Mariupol.
The metal works has become one of the last places of resistance against the Russians in Mariupol.
The video – believed to be filmed on 21 April – has not been verified by the BBC.
In the footage women and children – seen in a crowded room – can be heard saying they are now running out of food and water, and pleading to be evacuated from the besieged southern city.
Much of Mariupol has been destroyed in weeks of heavy Russian bombardment and intense street fighting.
This week, President Vladimir Putin called off a planned Russian assault on the steelworks, and ordered his troops to seal it off instead.