Aleksandra Buriko, and half of its managerial board resigned to make sure the firm avoids U.S. sanctions against its founder, billionaire oligarch, Oleg Deripaska.

The mass resignations were part of "the efforts that have been made by the management of the group to protect the interests of the company and its shareholders" since the sanctions were imposed last month, Rusal said in a May 24 statement.

Buriko resigned after the U.S. Treasury's Office of Foreign Assets Control (OFAC) announced new punitive measures against Russia in early April in response to Russia's "malign" activities around the world. The latest round of sanctions primarily targeted Russian oligarchs close to President Vladimir Putin, especially Oleg Deripaska - who had previously been interviewed by Robert Mueller - prompting Rusal shares to tumble while the price of aluminum soared.