Last month, Washington imposed sanctions on some of the largest Russian companies and businessmen, including Deripaska and its aluminum empire, because of Moscow's alleged interference in U.S. presidential elections in 2016.
The U.S. Treasury Department has given U.S. customers of the company until October 23 to wind down business with Rusal, and said it would consider lifting the sanctions if Russian aluminium tycoon Oleg Deripaska ceded control of the company.
Uncertainty over aluminum supplies has supported prices, which at ~$2,250/metric ton have jumped more than 10% since April 6.
In a statement issued in Hong Kong, where it is listed, Rusal said Deripaska, a non-executive director of the company, had stepped down as director.
It struck at allies of President Vladimir Putin to punish Moscow for alleged meddling in the 2016 USA presidential election and other so-called malign activities.
It said the decision was taken in order to "protect the interests of the company and its shareholders".
En+ also announced its directors had endorsed its chairman's plan to have sanctions lifted.
President of En+ Group, Oleg Deripaska attends an agreement signing ceremony with the Krasnoyarsk region's government, in Moscow, Russia December 12, 2017.
Evgeny Nikitin, head of Rusal's aluminum division, has been appointed by the board as the acting CEO of the company for a period from May 23 until the board appoints a new CEO.
"Opportunities to provide financing to the group on commercially reasonable terms will be very limited", it said. The sanctions have in effect locked the group out of the USA dollar economy and the company has...
Rusal also warned that under those circumstances it might not be able to maintain its operating performance at the level required to service and repay its debts and that could result in current creditors accelerating repayment.