Keshi dragged NFF to court last week for “wrongful dismissal and defamation.”
An anonymous source told journalists that “Keshi’s lawyers have demanded a billion Naira from the NFF as compensation for defaming their client.”
The letter from the Kaduna-based law firm was received by the NFF on Friday.
Keshi was sacked by the NFF on July 5 after its disciplinary committee investigated various allegations against him.
Four months ago, the 53-year-old coach signed a new two-year contract after his initial three-year deal with the NFF ran out at last year’s World Cup in Brazil.