The Russian governing bodies for weightlifting and rowing have lodged appeals with the Court of Arbitration for Sport (CAS) in a bid to overturn Olympic bans on their athletes.
The rowing governing body FISA deemed only six of 28 nominated athletes eligible for Rio while the weightlifting authority IWF banned the whole Russian team of eight from the Olympics.
"We have filed a lawsuit with CAS and are waiting for their response and will see whether we will receive it on Tuesday or not," Russian Weightlifting Federation president Sergei Syrtsov told TASS.
The International Olympic Committee decided against a blanket ban on all Russian athletes for the August 5-21 Games but rather left it to the sports federations to decide which Russians would be eligible to compete in Brazil, pending final approval by the committee.
The arbitration court has an ad hoc division in Rio de Janeiro which says it will handle cases within 24 hours.
Three banned swimmers and a wrestler have also made appeals to the court. At least 117 of Russia's 387 Olympic athletes have been banned from the Games.
Based on reporting by dpa, AFP, and TASS