Exxon Mobil has asked the Trump administration to let it proceed with an energy project with a Russian state-run company that was put on on hold when the Obama administration sanctioned Russia over its invasion of Ukraine, according to a new report.

Secretary of State Rex Tillerson negotiated the contract with Russia when he was CEO of Exxon Mobil. Russian President Vladimir Putin predicted at the time that the deal would be worth $500 billion, meaning that the waiver would be a substantial blow to the effectiveness of the energy sanctions imposed in 2014.