Argentina coach Marcelo Bielsa angrily hit out at Spanish champions Valencia on Wednesday after their midfielder Pablo Aimar failed to arrive for training with the South Americans.
Aimar was due to begin training with his country on Tuesday for Saturday's World Cup qualifier away to Peru.
"There's been a clear alteration of the rules on Valencia's part," said the normally placid Bielsa. "He played (in a league match) against Villareal on Monday when he shouldn't have done. He should be here with us."
His absence appeared to be a tit-for-tat reprisal after central defender Roberto Ayala, another Argentine international who plays for Valencia, was injured while playing at the Olympic Games.
Valencia said on Monday that Ayala would be out for up to two months after suffering knee ligament damage in the Olympic final against Paraguay in Athens on Saturday.
The injury came after Ayala had spent three months with Argentina, playing two World Cup qualifiers in Brazil and Argentina, the Copa America in Peru and Olympic Games in Greece as an over-age player -- all within FIFA rules.
The episode is the latest in a long history of club-versus-country disputes involving European clubs and South American national teams.
The Argentine sports daily Ole quoted a Valencia spokesman as saying that Aimar would stay in Spain.
"We went through all the necessary procedures, they didn't send him, they ignored the regulations and I don't know what will become of this situation," added Bielsa.
He added that Valencia were justified in being upset about Ayala but said that no rules had been broken.
"Valencia feel they have lost out because of the recent call-ups for Ayala and, it's true, he's been at the service of the national team for 90 days and this conspires against Valencia's interests," he said.
"But the rules say that I, as coach of the national team, am authorised to select a player for World Cup qualifiers, for the Copa America and the Olympic Games.
"So I selected him in accordance with the aforementioned regulations."