This satellite image from Planet Labs PBC shows damage at the Azovstal steelworks in Mariupol, Ukraine, Wednesday, April 27, 2022. AP
The images by Planet Labs PBC shot Wednesday show that concentrated attacks have greatly damaged a central facility at the Azovstal steelworks.
An estimated 1,000 civilians are sheltering along with about 2,000 Ukrainian fighters in the steelworks, a massive Soviet-era complex with a warren of underground facilities built to withstand airstrikes.
Mariupol, a strategic port city on the Sea of Azov, is viewed as crucial for the Russians in the war.
The new images come as UN Secretary-General Antonio Guterres visits Ukraine and plans to speak to Ukraine's president about his efforts to negotiate with Moscow for a corridor for people to leave the besieged area.