Sepp Blatter has resigned as FIFA president amid the ongoing corruption investigation into world football's governing body.
The 79-year-old Swiss called an extraordinary congress "as soon as possible", saying "a new president will be elected to follow me".
Blatter has held the role for 17 years but has come under increasing pressure following recent revelations.
Blatter told the press conference: "I will organise an extraordinary congress for a replacement for me as president. I will not stand. I am now free from the constraints of an election. I will be in a position to focus on profound reforms. For many years we have called for reforms. But these are not sufficient.
"I have thoroughly considered and thought about my presidency and the last 40 years in my life. These years were closely related to FIFA and the wonderful sport of football. I appreciate and love FIFA more than anything else.
"I only want to do the best for FIFA and my institution. I decided to stand again as the best option for football. The elections are closed but the challenges we face haven't come to an end."
Blatter's announcement comes after FIFA has admitted it paid $10million dollars destined for the South Africa World Cup to an account controlled by the disgraced former vice-president Jack Warner.
The payment followed a letter from the South African FA to FIFA secretary general Jerome Valcke.
The FAI, who had stated their intentions of voting against Blatter even before this latest scandal erupted, have welcomed last night's decision by the controversial administrator to step down from the world body.
"This is good news for world football and not before time. These are changes that we had called for and had hoped would come.
"We believe there is now an opportunity now for real change and reform at FIFA," FAI Chief Executive John Delaney said in reaction to Blatter's resignation.
"It is important that this opportunity to change the culture within FIFA at the highest levels is not passed up," added Delaney, who has been on the board of the FAI since 1999, has been at the helm of the FAI as Chief Executive for over 10 years and has a contract as CEO up to 2020.
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