Mexico football chiefs vowed to exclude domestic club players from the country's World Cup squad if they fail to report for a pre-tournament team training camp scheduled for later on Wednesday.
In a bizarre twist to Mexico's World Cup preparations with their opening game just five weeks away, the federation said players who skipped the get-together risked being ruled out of contention for the squad.
"Per instructions from the coaching staff, any player who does not report to the training camp today will be left out of the World Cup squad," the national team stated in a press release.
The standoff emerged this week after several internationals signalled they may not be able to join the camp, which is taking place outside of Fifa's designated international window.
They include two Mexico internationals who play for Liga-MX side Toluca, who are due to face Los Angeles FC later on Wednesday in the second leg of the Concacaf Champions Cup semifinals. The game is scheduled to kick off half an hour before the formal start of Mexico coach Javier Aguirre's pre-World Cup gathering.
The absence of the two Toluca players, Alexis Vega and Jesus Gallardo, has angered Liga-MX side Chivas de Guadalajara, which initially released five internationals to the national team despite currently preparing for a crunch playoff quarterfinal this weekend.
Chivas president Amaury Vergara subsequently recalled national team players Raul Rangel, Luis Romo, Brian Gutierrez, Roberto Alvarado and Armando Gonzalez.
Mexico coach Aguirre called up 20 players for the training camp - all of whom play in the Mexican domestic league - which is being held at the Mexican Football Federation's High Performance Centre in Mexico City.
In February, the clubs agreed to release their players following the conclusion of the domestic regular season and after the first leg of the Concacaf semifinals.
However, according to reports in Mexico, Toluca duo Gallardo and Vega - both called up by Aguirre - trained with their club on Tuesday.
Toluca head coach Antonio Mohamed reportedly plans to field them in the second leg of the Concacaf Champions Cup semifinals later Wednesday.
"Agreements are valid only when all parties respect them," Guadalajara president Vergara said on X.
Mexico's training camp is taking place ahead of World Cup warm-up matches against Ghana (May 22), Australia (May 30), and Serbia (June 4).
Mexico kick off the World Cup at the Estadio Azteca on June 11 with a Group A clash against South Africa.