UEFA opened disciplinary proceedings against Barca, Real and Juve on Tuesday, prompting the three clubs to issue joint statements saying they would not bow down to pressure from the governing body.
"I've told (UEFA president Aleksander) Ceferin that we aren't going to say sorry. And we don't plan on paying any sanction," Laporta told a news conference on Friday.
United were among six Premier League clubs who signed up for the breakaway league before withdrawing amid a storm of protest from fans, players and the British government.
In an emergency fan forum on Friday, the Manchester United Supporters Trust (MUST) urged the Glazer family to take immediate and decisive action to protect the future interests of the club.
Perez was one of the leading figures in the breakaway competition, which was unveiled last Sunday only to fall apart within days when all six English clubs involved withdrew and others followed.
"I don't need to explain what a binding contract is but effectively, the clubs cannot leave," Perez told Spanish newspaper AS on Saturday.
The ESL proposal collapsed on Wednesday as founding clubs withdrew one by one following a barrage of criticism from fans, governing bodies and even government officials who threatened to pass legislation to stop the league.
"They appreciate that very well and the people can read and can divide things from one another. The fans expressed their opinion, they were absolutely not happy.
UEFA president Aleksander Ceferin had said that the clubs who wished to breakaway would "suffer the consequences" but later said it was unlikely Real could be expelled from this season's Champions League.
"It's illogical (that Real could be expelled). We're going to play in the Champions League as that's our right," Zidane told a news conference ahead of his side's La Liga game against Real Betis on Saturday.
'Project Big Picture' was a plan put forward by Liverpool and Manchester United to increase funding for the 72 English Football League (EFL) teams but also included special voting rights for the biggest sides in the top flight.
"The Super League is just one way forward," breakaway founder and Juventus chairman Andrea Agnelli told Reuters on Wednesday of the plans involving 12 of Europe's top football clubs which included Manchester United and Real Madrid.
"It was a strange day for every football supporter, a surprise. We heard about the Super League the past few months but I was sure it was not going to happen," Ancelotti told reporters ahead of Friday's Premier League trip to Arsenal.
"The 12 clubs were wrong. They didn't take into consideration the opinion of the players and managers and the supporters.
City, along with Manchester United, Liverpool, Chelsea, Arsenal and Tottenham Hotspur, are the six Premier League clubs signed up for the new 20-club league announced on Sunday.
"If you ask me about these teams that have been selected I don't know why," the Spaniard told a news conference on Tuesday.
"The Premier League is considering all actions available to prevent it from progressing, as well as holding those Shareholders involved to account under its rules," the league said after a shareholders meeting to discuss the Super League proposal.
"The Premier League would like to thank fans and all stakeholders for the support they have shown this week on this significant issue.
"We're confident that this new competition will capture the imagination of billions of soccer fans all over the world and will be a new, exciting chapter for the game," Gazidis wrote in a letter to Milan's sponsors and commercial partners.
"The Super League will provide value and support to the whole soccer pyramid with greater financial resources."
"I'm here for the game. Everyone has their opinion but I'm not here to talk about that. I'll talk about the game tomorrow, the league, the Champions League - the rest isn't my job.
"You can say I'm sitting on the fence, and that's fine. Because what I like doing is coach, that's it."
"I know about it since yesterday. I'm here to be in the toughest competitions, that's why I'm at Chelsea," Tuchel told a news conference ahead of Tuesday's Premier League encounter with Brighton & Hove Albion.
"I was clearly not involved and my players were not involved in the decision-making process. My role is to be coach, to be focused and we have an important game coming up tomorrow."
The club, who were named as one of the 12 Founding Clubs on Sunday, confirmed this on Monday citing the COVID-19 pandemic for speeding up the instability in the existing European football economic model, while also saying they wish to improve quality of competition throughout the continent.
On Sunday, 12 Founder Clubs announced they intended to create and govern their own European competition, much to the incredulity of fans and leagues across the continent.
On Monday, several players rejected the idea and Herrera - whose French club are not among the 12 founding members - said the project would kill the dreams of fans across the globe.
"We invite you to attend on an urgent basis discussion with us regarding the details of the competition and how it can best be accommodated within the football ecosystem," the letter concludes.
"We do not seek to replace the UEFA's Champions League or the Europa League but to compete with and exist alongside those tournaments," the letter read.