The European Union’s top court turned away an appeal by Dmytro Firtash, the latest twist for the Ukrainian oligarch whose extradition from Austria the United States has been fighting for since his 2014 arrest in Vienna.

The October 24 ruling by the EU Court of Justice paves the way for the Austrian Supreme Court to hear Firtash’s challenge to the U.S. extradition request.

If the Austrian Supreme Court rules for his extradition, a final decision will then be made by the country's justice minister.

A former business partner of President Donald Trump's ex-campaign chairman, Paul Manafort, and one of Ukraine's wealthiest men, Firtash has been charged in a U.S. federal court in Chicago, as part of an alleged bribery scheme involving titanium supplies for aircraft giant Boeing.

His case has seen several twists, including being rearrested in Vienna on a Spanish warrant in February 2017, just minutes after an Austrian court cleared the way for his U.S. extradition.

It’s unclear when the Austrian Supreme Court will hear the case.

However, his lead U.S. lawyer, former federal prosecutor Dan Webb, told the Chicago federal court earlier this month that it was believed "that the Austrian Supreme Court will move quickly and Mr. Firtash could face extradition in a short time frame following the decision by the Court of Justice.”

Firtash, who has denied the charges, has been out on bail since shortly after his arrest, but barred from leaving Austria. His lawyers had argued that the U.S. prosecution was politically motivated.

Firtash’s wealth stems in large part from the lucrative natural gas trade in Ukraine, whose pipelines have long served as the key conduit for Russian gas supplies heading to Western Europe.

He is also considered an important financier of the Party of Regions political party, and was involved in hiring Manafort, then a U.S. political consultant and lobbyist, in 2005 to help rebuild the party after its then-leader, Viktor Yanukovych, was defeated for the presidency by Viktor Yushchenko following the 2004 Orange Revolution.

Firtash also had a brief partnership with Manafort in 2008 to invest in New York City real estate, although that deal never materialized.

Manafort was Trump's campaign chairman in 2016, until he was fired that August, amid revelations about his extensive work in Ukraine.

After a jury convicted him of bank and tax fraud in August, Manafort decided to cooperate with Special Counsel Robert Mueller in his sprawling investigation into Russian interference in the 2016 elections and interactions between Trump associates and Russian officials.