UEFA president Aleksander Ceferin lambasted the proposed European Super League on Monday, threatening once again to ban the clubs and players involved from continental and international competitions.

Twelve of Europe's top teams from England, Spain, and Italy announced Sunday that they had agreed to form a breakaway competition, a decision that has been met with widespread condemnation.

UEFA responded to the news' initial rumblings by maintaining its stance of imposing serious sanctions on those involved, and Ceferin followed suit by hitting out at the "cynical" plan.

"We are all united against this nonsense of a project," he said, as quoted by the BBC. "I cannot stress more strongly how everyone is united against these disgraceful, self-serving proposals, fueled by greed above all else.

"This idea is a spit in the face of all football lovers. We will not allow them to take it away from us."

Ceferin also singled out Andrea Agnelli, Ed Woodward, and Ivan Gazidis - executives at rebel clubs Juventus, Manchester United, and AC Milan, respectively - as "snakes" and "liars." The UEFA president is godfather to Agnelli's daughter and worked closely with the Italian while the latter was the president of the European Club Association (ECA).

"Andrea Agnelli is the biggest disappointment of all. I've never seen a person that would lie so many times, so persistently as he did. It's unbelievable," Ceferin said. "I spoke with him on Saturday afternoon and he said 'no worries, it's only rumours. I will call you in one hour.' Then he turned off the phone."

It's unclear if UEFA could enforce international bans on individual players who partake in Super League matches, but Ceferin maintained that position in his fiery rebuttal of the competition.

"Players who will play in the teams that might play in the closed league will be banned from the World Cup and Euros," he said. "We urge everyone to stand tall with us as we do everything in our power to ensure this never ends up in fruition."

Whether that move would apply to this summer's European Championship is unknown. UEFA's 55 member nations are scheduled to gather for an annual meeting on Tuesday.

In response to UEFA's threat of a ban, the Super League said it would defend itself in court.

"Your formal statement does, however, compel us to take protective steps to secure ourselves against such an adverse reaction, which would not only jeopardize the funding commitment under the Grant but, significantly, would be unlawful," the Super League wrote in a letter obtained by The Associated Press.

"For this reason, SLCo (Super League Company) has filed a motion before the relevant courts in order to ensure the seamless establishment and operation of the Competition in accordance with applicable laws."