NYON, Switzerland — FIFA detailed its plan for reshaping international soccer around playing the men's World Cup every two years despite European opposition that could lead to a boycott.

Joined by retired greats, FIFA unveiled the proposal Thursday but the pushback from Europe was immediate as UEFA president Aleksander Ceferin confirmed it could launch a boycott by its teams which have dominated soccer's marquee event since Brazil won in 2002.

"We can decide not to play in it," Ceferin said in an interview with British daily The Times.

About 80 former internationals including World Cup winners went to Qatar for two days of FIFA-hosted talks and emerged with consensus for playing the tournament twice as often.

"We all agreed with the new proposal of the calendar," said Brazil great Ronaldo, who went to four World Cups and won twice. He described FIFA's proposal as "just amazing."

Still, European soccer leader Ceferin said "as far as I know, the South Americans are on the same page" with resisting FIFA's plan.

"So good luck with a World Cup like that," Ceferin told The Times in the latest UEFA vs. FIFA fight since 2016 when he and Gianni Infantino were elected to the respective presidencies.

Infantino and his allies have since 2018 floated the idea of a biennial World Cup which European soccer has viewed as a commercial and competitive threat to its club and national team events.

Arsene Wenger has led the project since FIFA hired the former Arsenal coach last year to be its director of global development.

Details floated in recent media interviews and briefings were finally presented Thursday from Qatar in an overall plan to shape the schedule of international games from 2024. The FIFA-managed calendar mandates when clubs must release players to national teams.

More top-level tournaments and fewer qualifying games are the priority with a biennial men's World Cup the key takeaway.

Wenger said his priorities were less travel for players and less disruption for their clubs plus giving young talent worldwide "a chance to shine" by also playing more meaningful games.

The current system — that typically sees players based in Europe taking long-haul flights home throughout the season in short breaks for national-team games — could be replaced by a single block of fewer qualifying games in October.

International tournaments would occupy June each year, with players proposed to get a mandatory 25-day vacation in July before rejoining their clubs.

Wenger said the balance of players having 20% of their games for national teams and 80% for clubs would stay, though "in a more efficient way."

"I think it is an outdated (status quo)," he said. "It is not linked with the evolution of the modern game. We will not increase the number of games, we might even reduce it."

Retired greats like Germany's Jürgen Klinsmann, Roberto Carlos of Brazil, Didier Drogba of Ivory Coast and Denmark's Peter Schmeichel were enlisted to discuss changing the four-year World Cup cycle in place since the first edition in 1930.

"I don't think anyone disagreed on the frequency" of biennial World Cups, said Schmeichel, who played at just the 1998 World Cup. "It was a really, really long wait for an ambitious player like me to have the next possibility."

The global group of players' unions, FIFPRO, has not yet commented on FIFA's plans.

FIFA's process has angered many in European soccer who claim they were cut out of the consultation so far.

"Still nobody engaged us. It is very strange," Nasser al-Khelaifi, the Paris Saint-Germain president who leads the European Club Association, said Thursday at UEFA headquarters.

The European Leagues group added its opposition one day after the World Leagues Forum criticized FIFA's plans.

Wenger said FIFA could make a decision in December, though it would likely be ratified by its congress of 211 member federations next year.

Saudi Arabia, a close ally of Infantino, formally asked for a feasibility study into a biennial World Cup at FIFA's online members meeting in May.

Europe and South America have only a combined 65 of the 211 votes, with Africa's 54 now closely tied to Infantino, who is also an International Olympic Committee member.

FIFA can expect opposition from Olympic sports to adding another World Cup that would absorb billions of dollars in commercial revenue and a huge amount of media attention.

If approved, a biennial World Cup would likely move to odd-numbered years to avoid clashing with the Summer Olympics which open in late-July in 2028 and 2032.