MOSCOW (AP) — Russia says it will support companies hit by fresh U.S. sanctions as shares in aluminum producer Rusal plummeted.

Deputy Prime Minister Arkady Dvorkovich said in comments reported Monday by state news agencies that Russia will back the companies "if their positions worsen."

Shares in Rusal, which is controlled by the billionaire businessman Oleg Deripaska, plunged just over 50 percent on the Hong Kong stock exchange Monday.

Rusal says in a statement that the sanctions "may result in technical defaults in relation to certain credit obligations" and are highly likely to be "materially adverse to the business and prospects of the group."

Deripaska controls a business empire with assets in aluminum, energy and construction and has ties to former Donald Trump campaign chairman Paul Manafort, who once worked as his consultant.