A three-strong International Olympic Committee panel will have the final say on Russian competitors' eligibility for this summer's Rio Games.

The IOC's executive board met this weekend to assess final preparations in the host city and also rule on the process for approving Russian athletes put forward by their sports' international federations (IFs).

The IFs were left to decide on athletes' eligibility after the IOC decided against imposing a blanket ban on Russia following the McLaren Report into state-run doping in the country.

An IOC statement read: "The (executive board) decided to delegate the final decision on the acceptance of entries of Russian athletes to a review panel composed of three IOC executive board members: Ugur Erdener, Claudia Bokel and Juan Antonio Samaranch Jr.

"The review panel is due to make a final decision in the coming days."

Samaranch Jr is the son of the IOC's long-serving former president from Spain, who died in 2010. World Archery president Erdener, from Turkey, is the chairman of the IOC medical commission and a member of the World Anti-Doping Agency foundation board, while Bokel is the German chair of the IOC Athletes' Commission.

The panel will receive independent advice from the Court of Arbitration for Sport before making its decisions. Athletes who have already been ruled out by their IF and not granted CAS approval will not be put forward to the panel.

CAS has set up a base in Rio de Janeiro ahead of the Rio 2016 Games, and Russian swimmers Vladimir Morozov and Nikita Lobintsev have become the first athletes to bring cases there.

On Monday, swimming's world governing body FINA banned both, along with their Russian compatriot Daria Ustinova, because their names appeared in Canadian law professor Richard McLaren's damning report. Four more swimmers were withdrawn from the team by the Russian Olympic Committee as they had previously served doping bans.

A CAS statement said Morozov and Lobintsev had asked the body to rule as "invalid and unenforceable" the key section of the IOC executive board's ruling that specified nobody implicated in the McLaren report should be accepted for entry into the Olympics.

Morozov, 24, is a freestyle and backstroke specialist who has spent several years living in the United States, training and competing for the University of South Carolina.

He wrote in an open letter on Facebook: "Throughout the last 6 years I've been drug tested by doping control agencies at least once a month. I've been controlled by FINA, WADA, RUSADA, USADA, UKAD in competition and out.

"Throughout these years of constant doping control I have never had a positive test or a missed test."

Lobintsev is a 27-year-old freestyle swimmer who has acknowledged using the medication meldonium, which is often used to treat heart issues, but only before it was added to the World Anti-Doping Agency's banned list at the start of this year.

Russia's sports minister, Vitaly Mutko, has promised there will also be an appeal to CAS against the blanket ban of the country's weightlifting team.

Having already had two quota places removed for previous doping violations, the International Weightlifting Federation ruled on Friday that the remaining eight Russians would also not be allowed to compete in Rio following the reanalysis of samples from the Beijing and London Games.

A total of 225 Russians have so far been approved to compete in Rio, with 47 across boxing, golf, gymnastics, handball and taekwondo still waiting to hear from their respective federations.

Meanwhile, three athletes have had changes of nationality approved just in time for this summer's Olympics.

The decisions were announced following the conclusion of a meeting of the International Olympic Committee's executive board on Saturday.

Javier Garcia, who has represented Spain in water polo at two World Championships and a European Championship, has been cleared to compete for Croatia in Rio.

Sprinter Jennifer Madu has switched allegiance from the United States to Nigeria while Iszlam Monier will compete in judo for Sudan, having previously represented Hungary.

An IOC statement read: "The EB approved the change of nationalities for three athletes who will compete in Rio: Mr Javier Garcia Gadea (aquatics/water polo), from Spain to Croatia; Ms Jennifer Madu (athletics), from the USA to Nigeria; Mr Iszlam Monier (judo), from Hungary to Sudan."