WASHINGTON — The Treasury Department on Sunday removed Russian aluminum company Rusal from its sanctions list after a blacklisted billionaire and close ally of President Vladimir Putin, Oleg Deripaska, delivered on a promised plan to divest his majority ownership stake, the office said.

The issue had become a political controversy amid concerns the Trump administration was going easy on Russia, but many former Treasury officials and other sanctions experts said the move was made following longstanding policies under which the office does its work.