Manchester United and Chelsea have failed in their attempt to persuade Portugal not to take Cristiano Ronaldo and Tiago to next month’s Olympic Games.
Portuguese spokesman Felipe Felix said: “If it had been friendly games, we may have considered this option.
“But the Olympic Games is an official competition and the Fifa regulations are very clear regarding this.”
Ronaldo and new Chelsea signing Tiago are likely to miss six matches for their clubs.
Ronaldo had an outstanding European Championships as Portugal finished runners-up to Greece.
Manchester United boss Sir Alex Ferguson, who along with Ronaldo, will also miss his Argentinian defender Gabriel Heinze for the duration of the competition, admitted he was resigned to losing the pair.
“Regarding the Olympics, we’re just going to have to accept the situation,” said Ferguson.
“I’ve been in touch with both players and it looks as though there’s nothing much we can do about it.
“It isn’t fair on us or them but we just have to accept it.”