Swiss banks have frozen 1 billion of Swiss francs in the accounts of Russian metals tycoon Viktor Vekselberg over fears that they may be fined following U.S. sanctions against the businessman, Forbes reported.

"Swiss banks froze 1 bln francs on personal accounts of Viktor Vekselberg. Not only public banks (UBS, Credit Suisse) have blocked the funds, but also the private ones, including Julius Baer,” reads the message.

It is also noted that Vekselberg’s accounts may also be blocked by the Bank of Cyprus, whose 9,27% share is owned by a billionaire. Viktor Vekselberg is a Cyprus citizen since 2017.

A number of Swiss banks have repeatedly denied Vekselberg an access to major minority shareholding at Swiss industrial companies, including Sulzer, OC Oerlikon, and Schmolz + Bickenbach.

Vekselberg, Russia’s ninth richest man with an estimated net worth of $14.4 billion, was one of several Russian businessmen hit by U.S. sanctions this year for alleged meddling in the 2016 U.S. election and other “malign activity.” The tycoon has since been forced to cut his shares in foreign companies and repay more than $1 billion in loans made by European banks including JPMorgan, Credit Suisse and UBS.

As it was reported earlier, the U.S. Treasury Department has extended a deadline for investors to relinquish their interests in three Russian companies, a move that gives the firms time to reduce ties with Russian oligarch Oleg Deripaska and ultimately avoid U.S. sanctions, providing way for three Russian companies to avoid sanctions.

The new U.S. sanctions were announced on April 6 to fight what the U.S. Treasury called Russia's "malign" activities around the world. But Treasury Secretary Steven Mnuchin has said they were not intended to put Rusal, biggest aluminum producer and the world's second-largest producer, out of business.