Spain was absent from a group of 26 European countries who signed a joint declaration Thursday voicing their opposition to the contentious Super League football project, ahead of the UEFA Congress in Paris.

Stressing the need for open competition, the letter -- signed by sports ministers across the continent -- does not explicitly refer to the Super League but is clear in its opposition to the concept.

Only two clubs, Spanish giants Real Madrid and Barcelona, are still publicly attached to the Super League project, a closed competition intended to supplant the UEFA Champions League -- European club football's flagship event.

In the letter, the ministers "invite sport governing bodies to organise sporting competitions in compliance with the principles of openness, equal opportunities, sporting merit, link between annual performance in domestic competitions and all European competitions, financial solidarity, integrity and equity."

It comes in the wake of the European Union's Court of Justice (ECJ) ruling in December that FIFA and UEFA had infringed competition law by blocking the breakaway league.

European football was hit with a bombshell in early 2021, when 12 of its biggest clubs announced they had signed up to the planned Super League, triggering a furious backlash from fans and a stark warning from UEFA that clubs and players who took part would be barred from competitions like the World Cup.

Within 48 hours nine of the 12 rebel clubs -- including six from the English Premier League -- backed down and the project collapsed.

The promoters of the project, A22 Sports Management, have launched a legal challenge through the Spanish courts, which referred the question to the ECJ.

A22 responded to last December's ruling by crying victory and promising to launch a new project with 64 teams from across Europe split into three divisions with promotion and relegation within their system.

But many big clubs, even those who had tentatively backed the previous venture, said they would not support the new plan.

"(We) support the key features of a European sport model, including the pyramidal structure, the open system of promotion and relegation, the grassroots approach and solidarity, the sport's role in national identity," read the letter.

It also called for sports authorities to "preserve such key features and values and in this regard secure the balance between the economic dimension of sport and its educational and social functions".

Regarding Spain's absence from the list of signatories, a source within the Spanish sports council made direct reference to the Super League.

"The Spanish government decided not to sign the declaration... because the Super League matter is unresolved," the source said.

Spain is the only EU country where judicial procedures relating to the breakaway league are ongoing, they added.

Barcelona president Joan Laporta said last week the Super League "could start next season, or it will be in 2025-26, and if not, I will rethink everything."