Former UEFA Champions League winners Borussia Dortmund and Porto have rejected invitations to join the breakaway Super League.
The clubs made public statements less than 24 hours after six Premier League clubs and three clubs from both La Liga and Serie revealed their plans to set-up a new competition to rival the Champions League.
The Bundesliga club, who won UEFA's biggest club competition in 1997, revealed on Monday that they had received an invitation to join the 12 breakaway clubs but decided to turn the offer down.
"The board members of the European Club Association (ECA) came together for a virtual meeting on Sunday evening, where it was agreed that the board's decision from last Friday still stands," said Borussia Dortmund chief executive officer Hans Joachim Watzke.
"This decision dictates that all clubs wish to implement the proposed reforms to the UEFA Champions League. The ECA board members took a clear stance in rejecting plans for the establishment of a Super League."
Watzke added that: "both German clubs on the ECA board, FC Bayern Munich and Borussia Dortmund shared exactly the same stance throughout all discussions."
Jorge Nuno Pinto da Costa abordou os temas da atualidade, como o estado do campeonato e a proposta de criação da Super Liga Europeia 🔵⚪
Declarações completas em👉 https://t.co/KRfUZbLoEC #FCPorto pic.twitter.com/WQZ11d4A61
— FC Porto (@FCPorto) April 19, 2021
The president of FC Porto, Jorge Nuno Pinto da Costa, provided more detail to his club's decision not to accept their Super League invitation.
The Portuguese club, who won the Champions League in 2004, are backing the stance taken by their national association.
"As the Portuguese Football Federation is against this, and as part of UEFA, we cannot participate in anything that is against the principles and rules of the European Union and UEFA," said da Costa.
"If that goes forward, something that I have a lot of doubts about, UEFA will not end and it is certain that they will continue to have evidence.
"It must be recognized that the events organized by UEFA are the official events. We are not concerned with being or not, we are in the Champions League and we hope to continue to be for many years."
Meanwhile, UEFA president Aleksander Ceferin has warned that players who play in the Super League will be banned from playing in the European Championship and World Cup, despite not having the backing from FIFA at this point.