"To be now told that the I-League will no longer be the TOP LEAGUE is completely uncceptable and illegal and we pledge to fight this together as ONE FOOTBALL FAMILY which carries the tradition of football," the clubs said in a statement.
"We will see till July 3. If the ISL is officially announced as the top league, we will move the court," a club official said.
The AIFF has called for a meeting of its Executive Committee on July 3 and according to reports, the ISL will be made the top-tier league officially in that meeting, thus ending the long-standing impasse.
The AIFF had signed a Master Rights of Agreement with its commercial partners Football Sports Development Ltd (FSDL), a subsidiary of IMG Reliance, in 2010 which had stated that a new league (ISL) could be made the top division of Indian football and that the I-League could be reconstituted, replaced and/or discontinued (temporarily or permanently).
The clubs, including East Bengal, Mohun Bagan, Churchill Brothers, Minerva Punjab, and Gokulam Kerala, met at a plush hotel here, to decide on the next course of action.
The clubs also approached the AIFF's Appeals Committee to discuss the fines imposed on them for pulling out of the Super Cup earlier this year.
The Committee will decide on the fine in the next four weeks.
The AIFF and its commercial partner, FSDL, had slapped a fine of Rs 27.5 lakh on each of the six clubs for their "gross misconduct and in disciplinary acts".
Initially, they had levied a fine of Rs 10 lakh each on Aizawl FC, Churchill Brothers, NEROCA FC, Gokulam Kerala, Minerva Punjab and Rs 5 lakh on East Bengal. Mohun Bagan, who did not register for the competition, were penalised by the AIFF for the act but the decision is yet to come.
"We were asked to appeal again for the Rs 27.5 lakh fine slapped on us. Earlier, we had appealed against the Rs 10 lakh fine and now we have to appeal again. They will then compare the two appeals and make the decision," a source close to the development told .
Officials from NEROCA and Aizawl FC were absent in the meeting but said, in a letter, that they also stand united in the fight, a source said.
( With inputs from IANS )