Chelsea and Manchester City are wavering about joining the European Super League, according to a well-placed executive at another club approached to join the breakaway league, The Guardian reported.
British newspaper the Times reported that one of the English founding members was having doubts, while the Guardian named City and Chelsea as being both tempted to withdraw from the plans for a breakaway league.
The European Super League has generally received a very negative response in English football, with Liverpool fans protesting against their club's involvement outside Anfield and Leeds United's players warming up for their match against Liverpool in t-shirts emblazoned with the words "earn it" and "football is for the fans".
Those opposed to the breakaway believe that fewer than half the 12 clubs are considered "fanatics", who will back the Super League no matter what.
The others have joined because they believe they will be financially better off – either if it goes ahead or by wrangling concessions from Uefa – or they reluctantly entered because they feared missing out. Chelsea and Manchester City are believed to be in the latter camp.
However, another well-placed source, from an organisation opposed to the Super League, was more circumspect saying that while he hoped some clubs would reconsider he had no direct evidence they would.
Meanwhile, the pressure on the breakaway clubs intensified further on Tuesday as the Fifa president, Gianni Infantino, warned them they could not be "half in and half out" – a reference to playing in national leagues while turning out in a rival competition to the Champions League – and would have to live with the consequences of their actions.
"At Fifa, we can only and strongly disapprove the creation of the Super League," he said. "Of a Super League which is a closed shop, which is a breakaway from the current institutions. From the leagues, from the associations, from Uefa, from Fifa. Which is outside of the system. There is no doubt whatsoever of Fifa's disapproval of this."
Speaking at the Uefa Congress, Infantino said Fifa fully supported Uefa and the leagues. And he pointed out the "magic of football" – the bond from the lowest leagues of amateur football to the very top of the sport that had sustained for decades – risked being lost if the Super League went ahead.
"There is a lot to throw away for maybe a short-term financial gain of some," he said. "People need to think very carefully. They need to reflect, and they need to assume responsibility. They need to think not only of their shareholders but of all the fans who have contributed to creating what European football is today, what European football clubs are today. It goes back not only decades, it goes back more than 100 years. And we need to protect this."
"So, if some elect to go their own way, then they must live with the consequences of their choice. They are responsible for their choice. Concretely, this means either you're in or you're out. You cannot be half in or half out."
The president of the International Olympic Committee, Thomas Bach, has also come out against the European Super League, warning that "in this polarising environment, narrow self-interest and egotism are gaining ground over solidarity, shared values and common rules".
Speaking at the Uefa congress, Bach stressed he supported the European Sports Model, where the money went to the grassroots and success was based on merit. And he warned such a model was under threat from the "purely profit-driven approach that ignores the intrinsic values and social mission of sport".
Bach said: "It is under threat because the social mission of sport organisations is losing ground to the purely profit-oriented goals of commercial sport providers and investors. If everything is only looked at from a business perspective, if only the economic rules are applied to measure the impact of sport on society, then the social mission of sport is lost."