(Updates headline, adds comment, detail from list)
By Pavel Polityuk
KIEV, May 24 (Reuters) - Ukraine has put Russian businessman Oleg Deripaska, whose company Rusal owns a large alumina plant in the country, and other prominent Russians on an expanded sanctions list, a document on the president's website showed on Thursday.
It was not clear what effect the blacklisting would have as many Russian companies have already sought to wind up their Ukraine-linked activities due to earlier sanctions.
But restrictions on Deripaska could affect the operations of the Mykolaiv plant in southern Ukraine, which is the second-largest alumina asset of his aluminium business Rusal.
The Mykolaiv plant did not respond to a request for comment.
Kiev first implemented sanctions against hundreds of Russian companies and entities after Moscow's annexation of Crimea in 2014 and over its support for a pro-Russian separatist uprising in eastern Ukraine.
Earlier in May it expanded these restrictions to mirror those of the United States, which blacklisted officials and businesspeople around President Vladimir Putin in April. This was one of Washington's most aggressive moves to punish Moscow for its alleged meddling in the 2016 U.S. election and other "malign activity".
Ukraine's updated list was published online on Thursday, confirming sanctions on Deripaska as well as on other Russian tycoons such as Viktor Vekselberg, owner of Renova holding group, and Alexei Miller, the CEO of Russia's gas exporter Gazprom.
The additions to the list also include the Ukraine operations of Russian state news agency RIA Novosti. It did not reply to a request for comment.
On May 15, Ukrainian state security agents searched RIA Novosti's Kiev office and detained its director, accusing RIA of being used in an "information war" by Russia against Ukraine.
Kiev says the Kremlin uses an array of tactics to undermine and destabilise Ukraine, spreading propaganda while supporting the eastern separatists with troops and sophisticated weaponry and launching cyber attacks on Ukrainian infrastructure. Moscow denies the accusations. (Additional reporting by Natalia Zinets; Writing by Alessandra Prentice; editing by Matthias Williams and David Stamp)