A confidential document containing explicit and explosive allegations of corruption and financial mismanagement at the top of world soccer's governing body was made public on Sunday.
The document, prepared by FIFA general-secretary, Michel Zen-Ruffinen from Switzerland, is a searing attack on his former mentor and FIFA president Sepp Blatter.
"FIFA today is run like a dictatorship," wrote Zen-Ruffinen in the introduction to his his 21-page report which was submitted on Friday to the organisation's executive committee.
The increasingly bitter clash between the two men, both of whom are Swiss, looks set to snowball after the report was leaked to a Swiss newspaper and other media.
Marked "strictly confidential", the report claims Blatter's management and the bankruptcy of FIFA's marketing partner, ISL/ISMM, had cost the organisation up to SFr800 million ($500 million).
Zen-Ruffinen accused Blatter of making repeated unauthorised payments, including writing a cheque for $25,000 to a Niger refugee to dig up dirt on one of Blatter's critics.
Blatter, who is fighting to retain the FIFA presidency in a vote later this month, has denounced allegations of corruption as "crazy and unfounded".
In an interview with Swiss radio on Saturday, Blatter vowed to answer the charges levelled against him and clear his name.
He insisted the bitter fighting within the FIFA leadership would not affect the upcoming World Cup, but made it clear there would be no ceasefire.
"The general-secretary would do better to work more and play less at being the FBI and the CIA," he said.
His comments came 24 hours after Zen-Ruffinen called for a criminal investigation into possible corruption within the organisation.
At a press conference in Zurich on Friday, Zen-Ruffinen announced it was time for FIFA to "clean its house".Zen-Ruffinen said on Friday that his document contained evidence of misleading accounting practices, conflicts of interest and financial mismanagement.
Its release over the weekend has only served to deepen the atmosphere of scandal engulfing FIFA's top echelons.
In his report, Zen-Ruffinen contends that Blatter last year arranged for payments to former FIFA president Joao Havelange worth $55,000.
"The real background to these payments is questionable," he said.
He also says FIFA lost out on millions by giving 2002 and 2006 World Cup television rights to Germany's Kirch Media, and that the organisation was being sustained on as yet unearned income.
Blatter now says he regrets promoting his one-time protégé through the ranks to the top of FIFA, but insists he is prepared to run the organisation on his own, given that his general secretary and the executive committee "don't want to play with me".
He accused Zen-Ruffinen of being used as an election tool by his opponents, who include the powerful European football federation, UEFA.
Blatter is up against African soccer head Issa Hayatou in the May 29 election FIFA election.
In an interview with Switzerland's SonntagsZeitung, Blatter said it would take an "earthquake" to stop his re-election. He also said Zen-Ruffinen's report contained many factual errors.
Blatter is expected to respond to the claims when he returns from a trip to Asia.
swissinfo with agencies