Evraz PLC (LSE:EVR) has been sanctioned by the UK government, with assets frozen so no UK citizen or company will be able do business with them.
The reason given by the Foreign, Commonwealth & Development Office was that the company's Russia-based steel manufacturing and mining operations are "sectors of strategic significance to the government of Russia".
Announcing the sanctions overnight, the government department noted that Evraz produces 28% of all Russian railway wheels and 97% of rail-tracks in Russia.
"This is of vital significance as Russia uses rail to move key military supplies and troops to the frontline in Ukraine," the department said.
"Along with existing measures, this action will further deter companies operating in strategic sectors in Russia [and] further chip away at Putin’s financial reserves and siege economy, and support Ukraine’s continued resistance."
Since the invasion the UK has put over 1,000 individuals and over 100 businesses on its sanctions list.
Shares in Evraz have been suspended since 22 March, after falling over 85% since the invasion of Ukraine.