Liverpool manager Jurgen Klopp insisted his negative opinion of a European Super League had not changed and stressed the importance of the "competitive factor of football" ahead of Monday night's Premier League game at Leeds.
Six Premier League sides – Arsenal, Chelsea, Liverpool, Manchester City, Manchester United and Tottenham – are part of an initial group of 12 clubs seeking to establish a new 20-team continental competition "as soon as practicable".
AC Milan, Atletico Madrid, Barcelona, Inter Milan, Juventus and Real Madrid have also signed up as founding clubs, with three more expected to follow before the inaugural season.
But the plan has provoked widespread outrage, with high-profile figures from football and politics uniting to condemn the proposals.
Klopp, speaking to Sky Sports ahead of his side's game at Elland Road, stuck by his words from 2019 when he said he "hoped this Super League will never happen".
"It didn't change. My opinion didn't change," the German said.
"It is a tough one, people are not happy with that. I can understand that, but I cannot say a lot more about it because we were not involved in any processes – not the players, not me. We didn't know about it. The facts are out there and we will have to see how it develops.
"I have no issues with the Champions League, I like the competitive factor of football.
"I like the fact that West Ham might play in the Champions League next year. I don't want them to because we want to do that, but I like that they have the chance."
A number of banners appeared outside Anfield in protest against Liverpool's inclusion in the breakaway faction – with Klopp keen for the relationship between his players and the club's fans to remain undamaged.
"What I really don't like is that Liverpool Football Club is much more than some decisions and the most important part of football are the supporters and the team and we have to make sure that really nothing gets in between that," he said.
He added: "The boys did nothing wrong, apart from not winning all of the football games, so I really want to make sure everyone knows that."
Former Liverpool defender Jamie Carragher called on everyone involved in the sport to unite and battle against the proposals.
"My message to everyone is that these clubs think this is a done deal, I don't think it is," he told Monday Night Football.
"Supporters up and down this country can stop it and I really do believe it. At the forefront of that will be Liverpool, because I have seen it before.
"We have tribalism in this country, we have rivalry and that is what makes the game the way it is and that is what we love.
"Football fans get together – all of us in TV, pundits, players, managers get together and stop this.
"It can be stopped and I am convinced of it. Going forward that is what we need – marches on stadiums, supporters getting together. It should not be allowed to happen."
Former Manchester United defender Gary Neville, who spoke passionately against the proposals before confirmation came late on Sunday, hit out at the club's owners, the Glazer family.
"When I woke up and saw the statement and it had Joel Glazer's name on it, I thought this was a big problem," he said.
"He doesn't put his name on anything, that man. He is intelligent, he knows what he wants and he has parked his weasels and he has come out and it made me think, 'This is serious'.
"He is not backing down, he will try and push this through and, once he puts his name on it, he is going to try and force this through.
"They (the Glazers) have been through hell in the early years at Manchester United, they withstood it, stood it out and they don't care, so when I saw his name on it I really worried."
Neville's ex-United team-mate Eric Cantona felt it was a "shame" that fans had not been consulted.
Speaking on a video on his Instagram, the Frenchman said: "Since one year we have seen games on TV with the best clubs in the world and the best players in the world, and it was so boring, and it's still so boring, because the fans are not there – the fans singing, jumping, supporting their teams.
"The fans are the most important thing in football. They have to be respected.
"Did these big clubs ask the fans what they thought about this idea? No, unfortunately, and that's a shame."
The Premier League's all-time leading goalscorer Alan Shearer earlier urged the league to kick out breakaway clubs.
"These 12 clubs dropped a huge grenade on the sport with this announcement, and the Premier League should respond with a grenade of their own and say 'OK, you're going to be banned from the Premier League from next season'. That's how they should deal with this," he said via Coral.
Like Carragher, former England, Tottenham and Barcelona striker Gary Lineker believes fan-power can stop the plan. The Match of the Day host tweeted: "Football is nothing without its fans. We've seen that clearly over the last 12 months.
"If fans stand as one against this anti-football pyramid scheme, it can be stopped in its tracks."
Ex-Arsenal manager Arsene Wenger says the move goes against everything football is based upon.
Wenger, now FIFA's chief of global football development, told talkSPORT. "Football has to stay united – that is the most important thing – and based on sporting merits and overall to respect the history of European football. I believe personally that this idea will not go far."
Ian Wright played under Wenger at Arsenal and spoke out passionately against the Gunners' decision to be involved.
"I literally can't believe it when I saw Arsenal's name come up on the screen as one of the teams," he said in a video posted on Twitter.
"This is the same Arsenal that only a couple of weeks ago was commended for the tribute to David Rocastle.
"God, the man would be turning in his grave knowing what is going on now. Is this how far we have fallen?
"That we are getting into competitions because we are not good enough to get into them, so at the detriment of the English game we are getting the seat to the table we have no right to be at."
Political figures were also quick to condemn the Super League, with Prime Minister Boris Johnson saying football clubs were more than "great global brands" and needed to have a link with their fans and communities.
Speaking to reporters in Gloucestershire, Johnson said: "We are going to look at everything that we can do with the football authorities to make sure that this doesn't go ahead in the way that it's currently being proposed."