The Royal Spanish Football Federation (RFEF) has told ESPN FC that FIFA will back its decision to block a La Liga game in the United States this season.
Earlier this month, the RFEF received a request from La Liga for Girona's home match against Barcelona in January to be played in Miami.
The federation responded by telling La Liga and the clubs that it intended to veto the proposal.
La Liga president Javier Tebas said this week that he was continuing to work with the RFEF and the Spanish players' union (AFE) on finalising plans for the game to be played in Miami.
But in an email to ESPN FC on Friday, the RFEF said: "The RFEF has already replied by letter to La Liga -- they know that the game cannot be played.
"The RFEF has put everything in FIFA's hands, which will back the NO from the RFEF. EVERYONE'S answer is a NO."
La Liga players have opposed the staging of a game in the U.S. under La Liga's 15-year marketing agreement with Relevent Sports to promote the game in North America.
The AFE said La Liga had taken a unilateral decision and that the idea breached several articles of the collective agreement between the two groups.
La Liga needs the support of the RFEF as well as Spain's Sports Council, UEFA, CONCACAF and U.S. Soccer in order to move the Girona game.
"None of the institutions or authorities want this," the RFEF said. "Right now, La Liga has not requested a meeting.
"Tebas publicly said that he had requested a meeting with [RFEF president Luis] Rubiales and then had to publicly apologise, claiming there was "confusion".
The RFEF wrote to UEFA and FIFA last month to explain its intention not to authorise the game. FIFA has already expressed reservations about the plan for a U.S. match.
In an interview with CNN on Friday, Tebas said: "I would bet $10,000 that we play the match [in Miami]."
He insisted that he is working to change the attitude of the RFEF.
"I know both Spain and the sports world so I knew it would not be easy and that there would be some uproar," Tebas said. "It is an industry that is resistant to change so other things we have done have also been hard. But we have achieved them so I am pretty sure we are going to play in Miami. I think the Miami game is going to happen.
"As I have said before I know my country and its sporting institutions well and therefore we knew that this unrest was going to take place. I am not surprised by it. We have a strategy and we'll keep working towards being in Miami on Jan. 26 at the Hard Rock Stadium. I think that's a common strategy with the Federation to oppose the idea. I think the Barcelona and Girona players want to play in Miami. I think they'll be happy and I think we'll resolve this issue. It doesn't make sense that they would not want to play an official league game in the United States."
If Tebas's plans are finally approved, Eibar's chief executive Patricia Rodriguez said her La Liga side are ready to sign up for the next game in the United States, which would take place in the 2019-20 season.
"Of course we are in favour of it, we have sent an email to Javier Tebas telling him we want to play there," Rodriguez told reporters on Friday at the club's Ipurua stadium.
"I think it's a great opportunity for a club like Eibar, because you will have the attention of a place like the United States, which is hosting the World Cup (in 2026 alongside Mexico and Canada) and where the interest in football is increasing a lot.
"To go there and play a match against Barca and Real Madrid is a good opportunity for any club in La Liga."
Eibar are the smallest team in La Liga and are from a town of 27,000 inhabitants. Their stadium holds only 7,000 spectators and they were promoted to Spain's top flight for the first time in 2014 and have remained there since.
Eibar have two supporters clubs in the U.S., in Indiana and Philadelphia, and travelled to the States in 2016 for friendly games against the Philadelphia Fury and New York Cosmos.
Information from Reuters was used in this report.