Photo Credit:Getty Images.
World number one Novak Djokovic has resigned as president of the ATP player council to front a new association aiming to increase the power of the players.
But he faces opposition from Rafael Nadal and Roger Federer, who remain members of the council.
Britain's Andy Murray has not yet joined the male-only association and has called for the WTA to be involved.
The first players to sign up for the Professional Tennis Players' Association met on Saturday at the Billie Jean King National Tennis Centre in New York, where the US Open begins on Monday.
Djokovic first raised the idea of players union at the 2018 Australian Open. Since then a number of his peers have been agitating for a greater share of the revenue generated by the Grand Slams, in particular.
"I have read in the letter from the ATP that they think the ATP cannot co-exist with this association. I have to respectfully disagree," Djokovic said after winning the Western and Southern Open on Saturday.
"Legally, we are 100% safe, and we are allowed to form the player association. We are not calling for boycotts, we are not forming parallel tours. This is an important step for players, and for the sport as well.
"We just want to have our own organisation, that is 100% ours. We are definitely going to try and work with ATP, and all the governing bodies."
A document detailing plans and objectives for the new body, which will be called the Professional Tennis Players Association (PTPA) has already been distributed to players seeking their approval.
Meanwhile in a statement, the ATP Tour said: "We recognise the challenges that our members face in today's circumstances. However, we strongly believe that now is a time for unity, rather than internal division.
"We remain unwavering in our commitment to deliver for our players across all areas of our business, ensuring they receive maximum benefit from their years on Tour, and that their voices are heard."
The Tour also received support from the WTA, the ITF and the four Grand Slams, who said in a statement: "It is a time for even greater collaboration, not division; a time to consider and act in the best interests of the sport, now and for the future. When we work together, we are a stronger sport."