LaLiga president Javier Tebas feels "ashamed" by "the worst reputational crisis" he can remember in Spanish football as Barcelona face corruption charges for payments made to the former vice president of the refereeing committee.

Prosecutors last week alleged Barca had sought favourable treatment from match officials as part of an agreement which saw them pay Jose Maria Enriquez Negreira around €7 million between 2001 and 2018.

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The case has created growing tension across Spain, with supporters around the country protesting at games over the weekend and throwing fake bank notes on to pitches.

Barca say they paid Negreira for "technical reports on refereeing," but Tebas is not convinced by their reasoning and says the Catalan club and their president, Joan Laporta, are not handling the situation well.

"I feel ashamed that we still don't have a convincing explanation from them," Tebas told Movistar on Monday. "In fact, we have no explanation whatsoever from Barcelona and this is going to take time to resolve.

"I don't remember a time of such reputational crisis as this one. We have to see this through until the end. There are payments that were made and that is something that Barcelona have acknowledged. This is abnormal.

"It's understandable the tension that has been generated. We are not only risking Barca's reputation but that of the competition.

"What we have is a first statement from Barcelona that said that everyone [the other clubs] did it and it has become clear now that was not the case.

"Each time I read or hear something, I worry even more. I don't think Barcelona's position is adequate. They are playing the victims and I don't consider that the most appropriate way to resolve this situation."

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Meanwhile, Spain's Higher Sports Council (CSD) became the latest institution or club to confirm they will join the prosecutor's complaint against Barca for the payments to Negreira.

Real Madrid had announced on Sunday they would also seek join the case "in defence of our legitimate interests" after being the only top-flight club not to sign the initial statement by LaLiga teams condemning Barca's actions.

Speaking at an event on Monday, Barca chief Laporta continued to protest innocence and promised to fight those trying to damage the club's image.

"Barca are a club of values," he said. "We don't use that word to look good, but because values are a fundamental part of our sporting excellence. That is why Barca are admired and recognised around the world.

"It also means others, motivated by envy, try to erode our reputation with campaigns carried out in bad faith. There have been a series of fierce attacks aimed at staining the club's image that have nothing to do with reality.

"You can be sure that the board will defend the club with all our strength. I really want to face all those shameless people that are trying to smear the club's image."