RIO DE JANEIRO (AFP) - Daria Ustinova, one of seven swimmers from drug-tainted Russia banned from the Rio Games, is making a last ditch bid to save her Olympic dream with an appeal to the Court of Arbitration for Sport.

CAS confirmed that they had received an appeal from the 17-year-old backstroke specialist, who joins compatriots Vladimir Morozov and Nikita Lobintsev in appealing bans handed down after they were named in the McLaren Report outlining a state-run scheme to cover up positive drugs test results.

Ustinova, a three-time world junior champion, set a junior world record in finishing fourth in the 200m back at the 2015 World Championships in Kazan, Russia.

But she has already been twice linked to doping. She was reprimanded by Russian authorities after failing a test for a prescription steroid when she was only 14.

The status of the appeals from Morozov and Lobintsev remained fuzzy on Wednesday (Aug 3), a day after representatives for the two said they had been cleared to compete in Rio.

Swimming federation Fina, however, said that report was premature, and that only the three-person International Olympic Committee commission to review Russian entrants could confirm their participation - after receiving information on the case from CAS.

Lobintsev and Morozov were part of Russia's bronze-medal winning 4x100m freestyle relay team at the 2012 Olympics.