VIENNA (Reuters) - Russia may appeal to the Court of Arbitration for Sport over the decision by athletics' world governing body to uphold a doping ban on its track and field team, Russian athletics official Mikhail Butov told Reuters on Friday.

"We need to analyze the document. If there is a basis to do so, we will go there," Butov said when asked if Russia would take the case to the CAS, a Swiss-based organization that settles international sporting disputes.

He was scornful of the IAAF's decision that athletes who trained outside Russia and could show they were not tainted by the Russian system might still be able to compete at the Rio Olympics as neutral competitors. "How are they supposed to do that - in a white vest?" he said.

(Reporting by Mark Trevelyan; Editing by Toby Chopra)