Barcelona and Real Madrid have confirmed they will boycott next week's LaLiga summit in Dubai, which Los Blancos have labelled as "illegal".
Spanish top-flight clubs have been asked to attend the meeting on December 7 in which a number of topics regarding the league will be discussed.
However, LaLiga's two biggest clubs – who have been embroiled in a long-running battle with league chief Javier Tebas – will not be present in the United Arab Emirates.
In a statement released on Wednesday, Madrid questioned the location of the event and the timing.
"We believe the meeting is illegal, given that the clubs are being called to attend the meeting more than 5,000 kilometres away from LaLiga's headquarters," the statement read.
"It's completely unjustifiable to address in such an improvised and urgent manner, in the absence of the appropriate discussion and careful analysis, relevant modifications to LaLiga's internal regulations.
"It's completely inappropriate and deeply incoherent for LaLiga to undertake the economic expense of transporting more than 100 people to hold an event of this nature, at this time of year, in the United Arab Emirates, when the same could be held at LaLiga's headquarters without involving excessive costs.
"Clubs are going through very difficult times financially, burdened by the drop in income experienced in recent years, making it incomprehensible that excessive and unnecessary expenses should be incurred, in particular in the current economic climate.
"Real Madrid will not be sending any representative to Dubai for the reasons stated above and once again laments having to act against the irresponsible actions taken by the president of LaLiga, which are of unjustifiable economic cost and which seriously undermine the image and reputation of Spanish football."
Barcelona's statement, which was released at the same time, read: "Extremely relevant business is on the agenda concerning the modification of LaLiga's regulations that requires prior debate and a more extensive and participatory analysis to come to the best consensus that such a wide-ranging reform deserves.
"Barcelona's position has always been that of reaching consensual agreements after having examined the issue coherently and respecting all positions.
"For that reason, we do not believe it is the right time to travel to Dubai for an event that could take place at LaLiga's headquarters and once again we show our opposition to any form of action that we consider damaging to the rights and interests of the club."
LaLiga issued a response later on Wednesday in which it said the trip could "in no way be classed as illegal", and explained the choice of location was to help clubs grow internationally.
"With stops in Dubai and Doha, it is an opportunity to learn more about the region as well as to attend a World Cup game and an event that takes place in Dubai next week where various people from the footballing world are in attendance," the statement added.
"No club is obliged to travel to Dubai to participate in the assembly, since remote participation systems are in place, and they have been informed as such from the beginning."