May 28(Reuters) - Andretti Cadillac should buy an existing team instead of pushing for an 11th entry that has been rejected by Formula One's owners, the head of the governing body has told Reuters.

FIA President Mohammed Ben Sulayem, who last year called for more teams and fewer races, said that he remained supportive of increasing the number but that quality was more important than quantity.

"I have no doubt FOM (Formula One Management) and (commercial rights holders) Liberty (Media) ( LLYVB ) would love to see other teams as long as they are OEMs (car manufacturers)," the Emirati said at last weekend's Monaco Grand Prix.

"I would advise them (Andretti Cadillac) to go and buy another team, not to come as the 11th team.

"I feel that some teams need to be refreshed. What is better? To have 11 teams as a number or 10 and they are strong? I still believe we should have more teams but not any teams. The right teams.

"It's not about the number, it's about the quality."

U.S.-based Andretti Global is led by 1991 CART champion Michael Andretti, son of 1978 F1 world champion and 1969 Indianapolis 500 winner Mario.

The FIA approved the application last year but FOM rejected it while keeping the door open for 2028 when General Motors ( GM ), who own the Cadillac brand, might provide an engine.

The chairman of the U.S. House of Representatives Judiciary Committee this month launched an investigation.

"Without mentioning names, there are teams which are struggling...struggling with performance, struggling even with management," said Ben Sulayem.

"It's about having the right team, not to lose a chance or an opportunity where someone like GM (General Motors ( GM )) with a PU (power unit) is coming to Formula One.

"Imagine the impact. We have three races in America. We have such a huge fan base. But we don't have a proper (U.S.) team. I'm so happy to have Ford in (with Red Bull from 2026) but imagine having GM and imagine having American drivers."

U.S.-owned Haas, Renault-owned Alpine and Red Bull's second team RB have all been mentioned in the media as potential takeover targets, but none are openly for sale.

Williams are the only team with a U.S. driver, but Logan Sargeant appears on borrowed time.

Formula One has a $200 million entry payment, to be distributed among the 10 teams, for newcomers but that could rise to $600 million from 2026.

That might make buying an existing team more attractive, although valuations are already at more than $1 billion.

"We have to have a balance. Is $200 million too low? I believe $600 (million) is something where it is right for the current market," said Ben Sulayem of the threshold.

The FIA and F1, whose relations have been frayed, this month announced a joint strategic plan that was interpreted as peace breaking out.

"Peace is always good, you can't have all the time unnecessary issues," commented Ben Sulayem, who said a meeting with Liberty Media ( LLYVB ) boss Greg Maffei had been positive and talks on a new commercial "Concorde Agreement" were going well.

"We both understand that we need to go forward and the only way to go forward is to have much more clarity between us. We are on the same boat regardless and what we want is sustainability of the business," added the Emirati.

"We are with FOM when it comes to business. We are the partners and we have to also forget the small things and find a solution how can we address these issues."