UEFA have underlined their strong opposition to the formation of a European super league following reports of plans to launch a new continental competition involving Liverpool and Manchester United.
The Premier League giants are reportedly involved in talks over the creation of a new European Premier League, which it is claimed has the backing of the sport's world governing body FIFA.
But UEFA claimed such a competition "would inevitably become boring".
The European governing body, whose president Aleksander Ceferin last December branded reports of a world league "far-fetched" and "insane", said in a statement: "The UEFA president has made it clear on many occasions that UEFA strongly opposes a super league.
"The principles of solidarity, of promotion, relegation and open leagues are non-negotiable. It is what makes European football work and the Champions League the best sports competition in the world.
"UEFA and the clubs are committed to build on such strength not to destroy it to create a super league of 10, 12, even 24 clubs, which would inevitably become boring."
A leading fans' group called the reported plans for the new competition "the last nail in the coffin of the idea that football can be relied upon to regulate itself".
Wednesday's (AEDT) report comes just over a week after Project Big Picture proposals emerged, which were developed by Liverpool and Manchester United and publicly endorsed by EFL chairman Rick Parry.
The proposals were rejected at a Premier League clubs meeting last week.
Manchester United have so far declined to comment, while Liverpool have also been approached for a response.