Atletico Madrid reportedly intend to complain to FIFA over an alleged illegal approach made by Barcelona for striker Antoine Griezmann.
Speculation regarding the France international's future has been growing in recent days after it emerged that Barca president Josep Bartomeu met with the player's family.
Despite signing a five-year deal with Atletico in June, after seeing a big-money move to Manchester United fall through, Griezmann was rumoured to be on the brink of finalising a switch to Camp Nou as early as next month.
According to BBC Sport, however, Los Rojiblancos are unhappy with their domestic rivals' conduct in meeting with Griezmann's relatives - an approach they deem illegal and against FIFA rules.
The 26-year-old, said to be valued at around £87m, has seven goals in 19 La Liga and Champions League games this term.
