Former Liverpool manager Jurgen Klopp believes the Club World Cup is "the worst idea ever implemented in football" because of "serious fears" over player welfare.

The German is now Red Bull's head of global soccer and one of their teams, Red Bull Salzburg, qualified for this summer's tournament in the United States.

Klopp has often complained about players' workload and fixture congestion, and days before the Club World Cup, global players' union Fifpro released a report saying players should be allowed at least a four-week off-season break.

This year's Club World Cup is the first to feature 32 teams and 48 games, and saw Salzburg knocked out in the group stage.

During an exclusive interview with German newspaper Welt am Sonntag, Klopp talked about the expanded format and player development.

"It's all about the game and not the surrounding events - and that's why the Club World Cup is the worst idea ever implemented in football in this regard," he said.

"People who have never had or do not have anything to do with day-to-day business anymore are coming up with something.

"There is insane money for participating, but it's also not for every club.

"Last year it was the Copa [America] and the European Championship, this year it's the Club World Cup, and next year the World Cup. That means no real recovery for the players involved, neither physically nor mentally."

In September, a week prior to suffering an ACL injury, Manchester City midfielder Rodri said players were close to going on strike because of the increase in games, while team-mate Manuel Akanji suggested he would have to retire aged 30 as a result of the lack of breaks in the calendar.

In October, Fifpro filed a legal complaint with the European Commission over what it said was Fifa's "abuse of dominance", specifically related to the Club World Cup, and Fifpro representatives met with Fifa over the fixture calendar in January.

Klopp added: "I have serious fears, that players will suffer injuries they've never had before next season. If not next season, then it will happen at the World Cup or afterwards.

"We constantly expect the players to go into every game as if it were their last. We tell them that 70 or 75 times a year. But it can't go on like this.

"We have to make sure they have breaks, because if they don't get them, they won't be able to deliver top performances - and if they can't achieve that anymore, the entire product loses value."

Senior Fifa sources told BBC Sport earlier this month the protection of player welfare has been at the core of decision-making, pointing to initiatives such as a fund for players, additional substitutes in competitions and permanent concussion substitutes.

Suggestions the competition has contributed to further congestion in the fixture calendar were firmly dismissed, with a source saying it was "not caused by the Club World Cup".

It was pointed out that a maximum of seven Club World Cup games will be played by two teams every four years, with the slot for the competition replacing the one previously used for the Fifa Confederations Cup.