Russia hit the Kamet-Steel plant in Kamenske, Dnipropetrovsk region, reportedly using North Korean KN-23 ballistic missiles.
After Ukraine lost the Azovstal and Ilyich plants in Mariupol, Kamet-Steel became the country's second-largest steel producer.
Zaporizhstal and ArcelorMittal Kryvyi Rih were also hit recently, meaning Russia has struck all three of Ukraine's remaining major steel plants within a month.