The International Olympic Committee has said a three-member panel will make the "final decision" on which Russian athletes can compete in the Rio Olympics, set to begin in less than a week.

The panel will examine each case individually and make the "final decision" before Friday, IOC spokesman Mark Adams said late on Saturday.

A ban on individual Russian athletes followed a report by Canadian lawyer Richard McLaren for the World Anti-Doping Agency (WADA) stating that Russian doping of athletes had been organized by the sports ministry and aided by the Russian secret service at the 2014 Sochi Winter Olympics.

Rejecting calls for a blanket ban on Russia, the IOC decided on July 24 that individual sports federations should investigate athletes implicated in the report and decide who should be excluded.

So far, at least 117 individuals from the 387 that the Russian Olympic Committee wanted to enter have been excluded.

Russian sports minister Vitaly Mutko said Saturday he expected 266 athletes to compete. Boxing, golf, gymnastics and taekwondo federations have yet to report their decisions.

The three-member panel is made up of Ugur Erdener, president of World Archery and head of the IOC medical and scientific commission, Claudia Bockel of the IOC athletes commission, and Spanish IOC member Juan Antonio Samaranch.

Two Russian swimmers, Vladimir Morozov and Nikita Lobintsev, on Saturday launched the first challenge against the IOC sanctions excluding them from the games.

The Court of Arbitration for Sport (CAS) will hold an emergency session in Rio on Sunday to hear their appeal, according to sources close to the case.

Morozov, 24, and Lobintsev, 27, have called on CAS to declare "invalid and unenforceable" an IOC order for federations to exclude athletes implicated in the investigation into Russia's state-run doping system.

They were among seven Russians banned by the International Swimming Federation (FINA) last week after the order was published.

Morozov and Lobintsev have taken their action against the IOC and FINA.

Morozov said in a letter to FINA president Julio Maglione that he had never failed a drug test by Russian and international experts.

WADA president Craig Reedie, who called for a complete ban on Russian athletes in Rio, is to address the IOC meeting on Sunday.