FIFA will go ahead with a new 24-team Club World Cup starting in 2021, the ruling body's President Gianni Infantino said on Friday, setting the global body in conflict with Europe's top clubs.
Infantino said FIFA had made the decision at its council meeting on Friday.
The competition, however, immediately faced a boycott from Europe's leading clubs.
The European Clubs Association (ECA), which represents 232 European clubs, including all the leading teams, wrote a letter asking Infantino not make a decision now and saying they would not take part in the 2021 tournament.
Following Infantino's announcement, a spokesperson for the ECA said: "ECA clubs will not participate in 2021 CWC and will assess participation in editions of the competition post-2024."
The tournament would be held instead of the Confederations Cup in June 2021. No host nation has been decided yet.
"We went through a consultation process, spoke with everyone, some agree, others disagree, you have different views and positions," said Infantino.
"I am feeling very positive from the discussions and I am sure that at the end we will be very happy," he said.
Multiple sources told Reuters that representatives of UEFA, European football's governing body, had voted against the plan.
"I understand the situation in Europe with stakeholders, the leagues, the clubs, small clubs, big clubs, the players' union - it's more complex than other countries in the world.
"In football we are not waging war against each other - I am confident we can have a good and fruitful cooperation," he added.
Infantino said he believed a 48-team World Cup in 2022 in Qatar is "feasible", adding that FIFA would continue to study the options.
"If it happens - fantastic. If it doesn't happen - fantastic also," he said.
No decision will be made on expanding that tournament, with possible additional host nations, until June, Infantino said.
The FIFA Council also decided to use VAR video review technology at June's Women's World Cup in France.