MARIUPOL: Ukraine’s biggest steelmaker Metinvest said on Friday its enterprises would never operate under Russian occupation and that Ukraine had currently lost access to 30% to 40% of its metallurgy output capacity in the besieged city of Mariupol.

The company controlled by Ukraine’s richest man Rinat Akhmetov said that Ukraine, one of Europe’s biggest suppliers of iron ore, had also more than halved its iron ore production due to Russia’s Feb. 24 invasion.

Metinvest owns two vast steel works - Illich and Azovstal - in the city of Mariupol on the Sea of Azov and put the two facilities into a special “hot conservation” regime to protect equipment and prevent industrial accidents when the war began.

The city has since been devastated by weeks of shelling and siege and a dwindling Ukrainian force is trying to hold out despite being outnumbered and surrounded by a Russian assault.

Metinvest told Reuters in a statement that the sites had been damaged but that it was impossible to take stock and assess the scale of damage with fighting still raging.

It said: “We believe in the victory of Ukraine and plan to resume production after the end of hostilities. Metinvest’s metallurgical enterprises will never operate under Russian occupation.”

Metinvest’s plants in Mariupol accounted for more than a third of Ukraine’s metallurgical production, it said.

“The country has therefore lost 30-40% of its metallurgical production capacity, since the plants are not working.

We have no doubt that their work will be resumed, but for this Mariupol must remain Ukrainian,” it said.