Former FIFA president Sepp Blatter could now be facing an investigation by the FBI into his own activities.

Blatter announced his resignation yesterday.

Reports in the United States say Blatter himself is being investigated by the FBI in connection with the disclosure of a letter confirming a 10million US dollar payment was made via FIFA's executive office to disgraced executive Jack Warner.

Blatter's announcement comes just four days after he was re-elected for a fifth term and follows corruption charges against FIFA officials that caused the biggest crisis in the world governing body's history.

The final straw came when FIFA was forced to admit that it had paid the 10million US dollars destined for the South Africa World Cup to an account controlled by Warner.