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.

"Exxon has been seeking U.S. permission to drill with Rosneft in several areas banned by sanctions and applied in recent months for a waiver to proceed in the Black Sea," explained the Wall Street Journal, which reported on the waiver application. "The Black Sea request is likely to be closely scrutinized by members of Congress who are seeking to intensify sanctions on Russia in response to what the U.S. said was its use of cyberattacks to interfere with elections last year."

Tillerson has recused himself from Exxon-related matters, but the application still has the potential to galvanize Trump's Democratic opponents and Republican skeptics, if the waiver is granted.

"Removing barriers to Exxon drilling in the Russian Black Sea with a state-controlled company like Rosneft would not only jeopardize global progress on climate change and provide momentum for a similar waiver in the Russian Arctic, it would also send a message to Russia that it can intervene in any country, including the United States, with no consequences," Greenpeace, a liberal environmentalist group, said Wednesday. "Members of Congress must stand up for the separation of oil and state."

Exxon Mobil's request comes as Rosneft is looking for new sources of economic help, including an energy deal in war-torn Libya, which lacks a functioning national government. "It is important that in Libya, whatever government gets installed, it's not another puppet government of Russia," New York Rep. Eliot Engel, the top Democrat on the House Foreign Affairs Committee, told the Washington Examiner.