Two employees who stayed at the plant in the first days of the siege said that more than 2,000 civilians had stayed there, many of them relatives of the employees.
The Russian Defense Ministry called for a ceasefire by Wednesday in the plant area to allow civilians to leave, Russian state media reported. However, previous attempts to call off the fighting have failed.
The plant is spread over four square miles, a complex of buildings, smokestacks, blast furnaces and stacks of coiled and sheet steel, and has its own port facilities on the Sea of Azov.
One of Europe’s largest metal mills, it produced about 4.3 million tons of steel a year before the Russian invasion, according to Metinvest, a steel and mining conglomerate owned by Ukraine’s richest man, billionaire Rinat. Akhmetov.
The network of underground passages and rooms, now critical to the survival of soldiers and civilians in hiding, was originally built to transport equipment between buildings, according to Metinvest. There was no planned military use for the tunnels before the war, the company said.
The steel mill has been under heavy shelling, a Ukrainian commander, Lt. Col. Denys Prokopenko, said in a video recorded at the factory on Monday. “They use free-fall bombs, rockets, bunker busters, all kinds of artillery, both land and sea for indiscriminate attacks,” he said.
Russo-Ukrainian War: Key Developments
The Russians are trying to establish uncontested control of territory linking the separatist-controlled Donbas regions of southeastern Ukraine with the Crimean peninsula, which Russia seized in 2014. The holdouts in Mariupol are the last substantial hurdle that remains in the region.