The plant is owned by steel giant ArcelorMittal, which suspended operations there in September after a series of Russian ballistic missile strikes.
It did not immediately respond to a request for comment.
In a statement, Russia's defence ministry said the plant supplied steel products to the Ukrainian military-industrial complex.
It said Russian forces had also hit an electricity substation in the northwestern city of Zhytomyr and another steel plant in Zaporizhzhia, a city near the front line.
"Russia continues to target a steel plant that has not been able to resume normal operations following previous attacks," Oleksandr Myronenko, chief operating officer of Metinvest, said regarding the Zaporizhzhia attack.
"There is no logic to these strikes, just as there is no logic to the war itself," he said.
A cargo vessel in the Black Sea was also hit, the Russian ministry said, alleging that it was delivering military cargo to Odesa.
Later in the day, the ministry said Russian strikes during the afternoon had hit a vehicle-repair plant in Lutsk, an electricity substation in the western Ternopil region and another cargo vessel south of Odesa that it said was carrying military and dual-use cargo.
Reuters could not independently confirm the ministry's reports.
Ukraine, the United States and Russia could meet during a G20 summit in the US but the other two countries have not confirmed the meeting and other venues are also possible, Ukrainian President Volodymyr Zelenskiy said on Saturday.
The Group of 20 major economies, which includes the US and Russia but not Ukraine, is due to hold a summit in Miami in December.
"The meeting could then take place in the United States during the G20 summit. But there has been no confirmation yet from either Russia or the United States. It could also be held in a European country," Zelenskiy told reporters in a WhatsApp media chat.
He added: "This meeting could take place in one of the Middle Eastern countries. The United States has consistently mentioned the United Arab Emirates or Saudi Arabia."
Zelenskiy said Ukrainian negotiators had spoken to US officials on Friday but gave no other details.
He also said that Europe needed its own track for talks with Russia, with which relations are strained by Russia's war in Ukraine.
US President Donald Trump has declined to impose tougher sanctions on Russia over the more than four-year-old war, and Zelenskiy has criticised Trump for lifting sanctions on Russian diesel exports.
