Barcelona president Joan Laporta believes a conspiracy is at the root of allegations the club are facing over payments to a company owned by a former top referee.
A corruption complaint was filed last week by Spanish prosecutors against Barcelona, concerning payments allegedly made to a business run by Jose Maria Enriquez Negreira.
Negreira, once a top match official, was latterly vice-president of Spain's Technical Committee of Referees (CTA).
It has been claimed the total payments from Barcelona exceeded €7million, dating from 2001 to 2018. Newspaper El Pais last month reported Enriquez Negreira's company – DASNIL 95 SL – produced written reports and DVD assessments of referees for Barcelona prior to games.
Real Madrid have said they are ready to appear at any trial that stems from the investigation, and with remarkable timing there is a Clasico coming up on Sunday, with Barcelona at home to Madrid.
Laporta addressed supporters on Friday, telling them to trust Barcelona's side of the story.
"This Sunday we have a great game," Laporta said. "I ask you to come to cheer on the team more than ever. We have a great opportunity to get closer to our goal this season, which is to win the league. A great opportunity."
Barcelona lead the way in LaLiga by nine points from defending champions Madrid.
"The campaign we are suffering is not by chance, you all know this," Laporta said of the allegations. "Its objective is, in the short term, to destabilise the team, and in the medium term to control Barca. I will have time and I want to explain to you who, why and how they want to orchestrate this campaign.
"Have no doubt that we will defend ourselves. And we will not only defend ourselves, we will attack. But now we must be focused on encouraging the team this Sunday because, as I told you, their first objective is to destabilise the team."
Laporta offered no clarity regarding who he believes might be out to destabilise the club, and why they would have that motivation.
He told fans: "We have to focus on encouraging the team, our players, our coaches, so that they win the game. I think that we should not be focused on other aspects that could divert the attention of our players from concentrating on the game to win it. Because it is essential.
"Therefore, come this Sunday to cheer on the team more than ever. Let's encourage Barca because we love Barca. Long live Barca."