Three heavyweight European football clubs, Barcelona, Real Madrid and Juventus may face sanctions from the Union of European Football Associations (UEFA) as they refused to approve the "reintegration measures" of the European football governing body over the European Super League issue, hinted UEFA president Aleksander Ceferin on Friday.

In response, the three clubs released a joint statement on Saturday, calling UEFA's move "intolerable under the rule of law." "Tribunals have already ruled in favor of the Super League proposal, ordering FIFA and UEFA to, either directly or through their affiliated bodies, refrain from taking any action which may hinder this initiative in any way while court proceedings are pending," reads the statement, which also criticized UEFA for refusing "to establish any adequate channel of communication."

Three weeks ago, 12 of Europe's top football clubs – Manchester United, Liverpool, Manchester City, Chelsea, Arsenal, Tottenham Hotspur, Barca, Real, Atletico Madrid, Juventus Inter Milan, and AC Milan – announced the establishment of a new top football league named Super League. It was a crystal-clear breakaway attempt from the UEFA-governing board.

However, in less than 48 hours, all six English clubs quitted, followed by Atletico and the two Milan teams. The nine soon cut deals with UEFA for how they will be handled.

First, the nine clubs will pay UEFA combined 15 million euros (about $18.2 million) as a "gesture of goodwill," in UEFA's words.

Second, the UEFA will withhold five percent of the revenues from competitions of the nine clubs for the next season.

Third, if the nine clubs play in any other unauthorized competition, they will be fined 100 million euros (about $121.6 million). If they breach any other commitments to UEFA, the fine will be 50 million euros (about $60.8 million).

"The measures announced are significant, but none of the financial penalties will be retained by UEFA. They will all be reinvested into youth and grassroots football in local communities across Europe, including the UK. These clubs recognized their mistakes quickly and have taken action to demonstrate their contrition and future commitment to European football," said Ceferin.

However, since Barca, Real and Juventus turned down the deal, they will face other punishments, which will be probably tougher.

"The same cannot be said for the clubs that remain involved in the so-called 'Super League,' and UEFA will deal with those clubs subsequently," said Ceferin. He told AP that the three teams could be banned from the UEFA Champions League.

(Cover photo designed by CGTN's Li Wenyi)