It had jumped to a seven-year high last week.
Treasury gave Americans until October 23 instead of June 5 to wind down business with Rusal.
"They are I think interested in a unified approach on how we express our profound concern and our disagreement and how we will work together to address them", said the official, who spoke on condition of anonymity.
Countries and companies from around the world have been lobbying the U.S. government to soften the sanctions against Rusal because it was increasing clear they were causing severe disruption to global commodity markets, not only for aluminium, alumina and bauxite. Hong Kong's Hang Seng declined 0.5 percent.
MERGER MONDAY: Utility Vectren gained 5.2 percent to $68.96 after it accepted an offer from rival CenterPoint Energy worth nearly $6 billion, or $72 a share.
The Treasury said that it wanted to mitigate the consequences for those affected by the sanctions because it wanted to target Russian oligarch Oleg Deripaska, Rusal's ultimate owner, and not "the hard-working people who depend on Rusal and its subsidiaries". In that same action, OFAC designated EN+ Group for being owned or controlled by, directly or indirectly, Oleg Deripaska and other entities he owns or controls.
On Monday morning, the U.S. Treasury threw a potential lifeline by making clear it's not pushing for the company's collapse.
Russian Federation to move air defenses to Syria 'soon,' warns Israel against attack
He said: "Now, we have no moral obligations". "We took into consideration their claim that this could destabilise the situation". He also said that he was convinced Russian President Vladimir Putin and U.S.
Ex New York mayor Giuliani joins Trump legal team
In addition to Giuliani, two former federal prosecutors, Jane Serene Raskin and Marty Raskin, are joining Trump's legal team. He also intensified his public criticism of the Mueller investigation, calling it "an attack on our country".
Grieving Popovich will not return for Spurs' playoff game four
Manu Ginobili and Tony Parker - franchise cornerstones for 16 and 17 years, respectively - might retire this summer. The Spurs confirmed the news with a statement Wednesday after Popovich had run the Spurs practice as usual.
And Brian O'Toole, a senior fellow at the Atlantic Council, said that Rusal's effort to get off the sanctions list may turn out to be successful. Deripaska's spokeswoman wasn't immediately available.
European leaders have worked to persuade U.S. President Donald Trump to ease sanctions on Russia, including measures against Russian aluminum producers, with the presidents of France and Russia poised to visit the White House this week.
Mnuchin said "impact on our partners and allies" factored into the reprieve.
Rusal now has more time to sell off its supply.
Last week, aluminum rallied to its highest since mid-2011 on fears the global market could face shortages as a result of the USA sanctions.
Energy futures on the other hand fared much better, with front month Brent crude oil futures on the ICE tacking on 0.46% to see the day out from $74.40 a barrel. Or so markets seem to believe: Shortly after Mnuchin's announcement Monday, global aluminum prices nose-dived.