Dmytro Firtash, one of Ukraine's most influential oligarchs

An Austrian court on Thursday rejected a request to extradite to the United States Ukrainian oligarch Dmytro Firtash on bribery charges.

Firtash, 49, one of Ukraine's richest men and previously a close ally of ousted former president Viktor Yanukovych, was arrested in Austria in March 2014.

The US issued a warrant for him last year on charges of corruption linked to titanium mining in India.