As opposition to FIFA's controversial proposals, guided by president Giani Infantino, widened, CONCACAF, the regional body for North and Central America and the Caribbean, joined UEFA in rejecting the plans, although stopping short of threatening a boycott.
UEFA member associations gathered virtually for a crisis meeting and afterwards issued a statement that puts them on a direct collision course with the world's governing body.
"No UEFA national teams will participate in any FIFA competition for so long as these proposals remain alive, unless this proposal has been abandoned in its entirety and binding assurances have been given that FIFA will never again open its governance or competitions to private ownership," it read.
FIFA issued details of their plans to create FIFA Forward Enterprise (FFE) after media reports were published on Tuesday afternoon.
FFE would be owned and controlled by FIFA, the global body said, but the intention is to sell minority stakes to private investors.
The lead investor is proposed to be Thrive Eternal, a company founded by Joshua Kushner, the brother of United States President Donald Trump's son-in-law, Jared Kushner.
"UEFA and its 55 member associations stand as one," European football's governing body said in their statement.
"We unanimously and unequivocally reject FIFA's proposal to transfer ownership interests in the World Cup and other FIFA competitions to private investors.
"The World Cup cannot be treated as an investment product. It is one of football's greatest sporting legacies. No part of it should ever be surrendered to private investors. The World Cup is not for sale."
FIFA said the plans would enable them to make significant increases to the development funding available to national associations around the world – up to $A14.2 billion ($US10 bn) – in the three-year cycle between 2027-2030.
Associations were asked to make a decision by September 19 on whether they supported the idea of private investment.
The key concerns of UEFA and others were that, by opening up to private equity, pressure would grow for FIFA competitions to be bigger and ever more frequent, placing pressure on the rest of the calendar and raising concerns of fans facing ever higher ticket prices.
A Football Association spokeswoman said the English governing body stood "shoulder to shoulder" with their European colleagues and added: "We oppose FIFA's plans – the FIFA World Cup belongs to football and always will."
CONCACAF said their membership expressed "deep concerns about the lack of due process surrounding the proposal, a short deadline and the absence of any review or approval by relevant FIFA governance bodies."