Sepp Blatter has lodged an appeal against his 90-day ban imposed by FIFA's ethics committee.
Blatter was relieved of his duties as FIFA president on Thursday after the ethics committee's decision, but he has lodged an immediate appeal.
Klaus Stohlker, Blatter's friend and adviser, told Press Association Sport: "He has appealed already to FIFA's Appeal Committee. He is defending his position and he is sure that he will be found not guilty."
The New York Times reported that Blatter filed an official appeal on Thursday night through a letter sent by his lawyer to the head of FIFA's ethics committee.
According to the Times, Blatter's lawyer demanded a hearing as well as access to the committee's case file. The appeal reportedly says Blatter should not be suspended until he is proven guilty in the Swiss investigation.
The appeal also criticised the committee for not making Blatter aware of his suspension before releasing the news publicly.
Blatter and UEFA president Michel Platini were both handed 90-day suspensions by the committee while investigations take place into a £1.35 million payment to the Frenchman.
Platini has also announced that he will challenge the ban, and the decision will go to the FIFA appeals committee.
The timing of the provisional ban could hardly be worse for Platini, who wanted to run in the election to succeed Blatter as president but, with nominations closing on Oct. 26, those plans lie in ruins.
UEFA's 54 member associations will convene Thursday in Nyon to discuss the crisis, and there is expected to be an emergency FIFA executive committee meeting in Zurich the following week.
Football Association chairman Greg Dyke has said the English governing body will drop its support for Platini if the ethics committee decides there has been wrongdoing.
However, French Football Federation (FFF) president Noel Le Graet reaffirmed his backing for Platini.