This follows the sending of a letter by EOC President Patrick Hickey in which he criticises a clause in the contract for the new event - due to be co-hosted in Glasgow and Berlin - forbidding Federations "competing in another multi-sport continental event within a year of the conclusion of the 2018 European Sport Championships".

Such a rule would seemingly include the EOC-organised 2019 European Games and both summer and winter editions of the European Youth Olympic Festival.

Hickey claims the requirement - supposedly instigated by the event organisers at European Sports Championship Management (ESCM) - would violate both the Olympic Charter and competition law of the European Union.

"ESCM expect your federation to sign this contract with them (outside of the usual contract with the media partner EBU and the host city) which gravely infringes EU Competition law by (i) restricting competition within the marketplace and (ii) attempting to instigate the foreclosure on the market of multisport events in Europe," the Irishman wrote in the letter, obtained by insidethegames.

"This attempt to restrain your federations trade, manipulate the sports market in Europe and generally threaten the great institutions of European sport with an ultimate aim of a takeover by commercial organisations is completely against the Olympic Charter and IOC (International Olympic Committee) Agenda 2020 and could lead to serious consequences for ESCM."

Hickey claims to have already raised the matter with the IOC and its President Thomas Bach and hopes to do so in more detail at next month's meeting of the IOC Executive Board, of which he is a member.

The EOC have already taken legal advice from law firm Sheppard, Mullin, Richter & Hampton, who claim the "chief aim of such a clause is to restrict competition between the European Championships carried out by ESCM and its current and potential competitors by curtailing the freedom of action of the Federations".

This advice has also been sent to the Federations.

ESCM have disputed having inserted such a clause, with director Jon Ridgeon claiming last month that they "wouldn't dream of blocking any Federation from competing at another multisports event".

Ridgeon claimed instead that they had come to a "collective decision that no other official European Championships would be held at multisport events".

He has now promised to reassess the details of their contracts to ensure full-compliance with all relevant laws.

"No complaint has been directly addressed to ESCM," the Briton told insidethegames following the sending of the EOC letter.

"All the contents of the European Championships agreements are confidential, but we have always made every effort to ensure full compliance with all applicable laws.

"Naturally, we have been reviewing any claims made that they are not in compliance."

The European Championships, due to consist of continental competitions across seven sports taking place simultaneously in Glasgow and Berlin in 2018, are seen as a rival to the EOC-organised European Games, first held in Baku last year and due to take place for a second time in 2019.

Athletics is scheduled for the German capital at the European Championships, while aquatics, cycling, golf, gymnastics, rowing and triathlon action would all take place in the Scottish city.

Neither golf nor rowing featured at Baku 2015 or are expected to be on the European Games programme in 2019.

But the other five were all contested in some form in the Azerbaijani capital and are set to be showcased once again at the second edition.

insidethegames has been told by the continental Federation President of one of these five sports that they are "fully in control" of all their decisions regarding multisport participation and the European Championships, and would not be restricted by the ECSM.

"Someone is trying to make this a bigger issue than it is," they claimed.

This all marks the latest dispute between sporting events which are "official" and with supposedly unsanctioned rivals after the International Basketball Federation (FIBA) announced its "full support" of FIBA Europe's decision to ban 14 teams from international competition for backing the unsanctioned EuroLeague, currently the continent's premier club competition.

Hickey claimed last month that this decision was needed to protect the integrity of sport.

Russia is the "preferred choice" of the EOC to host the 2019 European Games, Hickey reiterated in his letter, but the country's Sports Minister Vitaly Mutko said earlier this month that they "never sent" an application and are "absolutely busy" until 2020.

He also claims to "support all efforts which benefit the sporting landscape in Europe".