The United States Anti-Doping Agency (USADA) and the Canadian Centre for Ethics in Sports (CCES) made the claims ahead of the publication of Richard McLaren’s report into allegations of state-sponsored doping at Sochi 2014.

The letter, addressed to the IOC and obtained by Reuters, is based on what the USADA and the CCES believe will be the findings of McLaren’s investigation, due to be published in Toronto on Monday (July 18).

insidethegames understands a number of National Anti-Doping Organisations (NADOs) have expressed early support for the letter.

It was circulated by World Anti-Doping Agency (WADA) Athletes Commission head Beckie Scott by e-mail and was signed by USADA chief executive Travis Tygart, who has previously lobbied for a full Russian ban at Rio 2016, and counterpart Paul Melia.

The document will be sent to the IOC once McLaren has released the eagerly-anticipated report.

Hickey, who is also the President of the European Olympic Committees (EOC), said he was "shocked and concerned on many levels" by the letter, which outlines why Russia should be excluded from all sports on the programme at next month's Games in Rio.

The Irishman believes the independence of the investigation led by McLaren, a member of the WADA Independent Commission whose reports led to Russia being banned from track and field events at Rio 2016 by the International Association of Athletics Federations, has been "compromised" and claims it is "clear that only athletes and organisations known to support a ban of the Russian Olympic Team have been contacted".

He also feels that there seems to have "been an attempt to agree an outcome before any evidence has been presented".

"Firstly, the McLaren Report is meant to be a totally independent report that must remain totally confidential until its publication on Monday, July 18 in Canada," Hickey said in a statement sent to insidethegames.

"It is clear from the e-mail and letter that both the independence and the confidentiality of the report have been compromised.

"Such interference and calls ahead of the McLaren Report publication are totally against internationally recognised fair legal process and may have completely undermined the integrity and therefore the credibility of this important report.

"I have to question on what authority the US and Canadian Anti-Doping agencies prepared their letter and what mandate they have to lead an international call for a ban of another nation in the Olympic family."

In the e-mail, Scott reportedly requests signatories from Europe but Hickey claims the EOC Athletes Commission chair Jean-Michel Saive was not informed or consulted.

"Yet I note from her email that three European NADOS 'amongst others' have been approached to sign," added Hickey.

"It is clear that only athletes and organisations known to support a ban of the Russian Olympic Team have been contacted.

"Whilst I fully understand and share international concerns over the recent doping allegations, we cannot allow any individuals or groups to interfere or damage the integrity of fair and due legal process."

The McLaren report will address damning accusations made by Grigory Rodchenkov , the former head of the under-fire Moscow Anti-Doping Laboratory before turning whistleblower, in the New York Times. 

He alleges that up to 15 Russian medal winners at Sochi 2014 were implicated in a clandestine operation in which doping samples were switched for clean ones.

Rodchenkov, the subject of a criminal case from Russian Federal investigators, alleged that the state-sponsored scheme involved athletes ingesting a "three-drug cocktail" of banned steroids which were mixed with alcohol.

It also featured as a covert system to replace the urine of affected medal winners with clean samples using soda containers and baby bottles, he claimed.

WADA President Craig Reedie has vowed to respond “firmly and effectively” should Rodchenkov’s allegations be proven, admitting it would be a “high-profile moment that we will have to deal with".

"Obviously in considering that scenario, a scenario we of course hope does not unfold, the global group needed to have something concrete to look at to assess whether or not it made sense and reflected each participants views (hence a draft letter was circulated)," Melia told insidethegames. 

"Whatever version of our working document was seen by the media was just that - an internal working document exploring a possible course of action if the evidence produced by Professor McLaren is clear, convincing and irrefutable with respect to systemic, state-sponsored doping in Russian sport.

"The global group absolutely has not contacted Professor McLean nor attempted to influence him in any way and we are certainly not aware of any of the contents of his report. 

"Mr. Hickey’s comments in this regard are surprising."

If the report supports Rodchenkov's accusations, calls for Russia to be exiled from every sport at Rio 2016 are likely to gather pace.

"We always want universal inclusion at the Olympic Games, but we can’t be blind to the evidence before us, and if we – as those who cherish the Olympic values - are not preparing for all potential outcomes, then we are not fulfilling our promise to clean athletes," Tygart said in a statement sent to insidethegames.

Russian competitors in track and field have been able to apply for eligibility for the Games despite the ban if they can prove they were tested outside of the nation.

A total ban on Russian athletes at next month's Games is likely to receive opposition from several International Federations (IFs), including the International Volleyball Federation (FIVB).

Ary Graça, President of the FIVB since 2012, said he would not support a blanket ban and hopes to have Russian volleyball players in Rio.

The Brazilian believes there is "no doping" in Russian volleyball as all of the tests done on players from the country have been conducted outside of the nation.