LetterOne is one of Pamplona's limited partners (LP) and was set up almost a decade ago by Fridman and Petr Aven.

The pair stepped down from LetterOne in early March following Russia's invasion of Ukraine but Pamplona decided to part ways with the firm to safeguard its portfolio companies from the fallout of the war.

The buyout firm, which has offices in London and New York, said it would wind down three funds linked to LetterOne, adding the decision had been approved by its board and would be effective on March 25.

"Such a process is irrevocable and will be conducted in accordance with all legal and regulatory mandates as required," Pamplona said in a statement.

It added that the wind down could be executed via the sale of LP interests to third parties as well as through the sale of direct investments.

(Reporting by Pamela Barbaglia in London; Editing by Catherine Evans and Matthew Lewis)

By Pamela Barbaglia