Atletico Madrid have accused Barcelona of running a "smear campaign" and "fake news" over their attempts to sign Julian Alvarez.
Barcelona completed the £69m signing of Antony Gordon on Friday and have been linked with a big-money move for Argentine striker Alvarez.
Atletico insist the 26-year-old is not for sale and value him as high as £130m.
The club responded to social media posts about an imminent Barcelona bid for Alvarez by mocking up parody posts of Barcelona stars Lamine Yamal, Pedri and Raphinha in Atletico shirts.
The posts also included joke bids for each player, including the offer of Bad Bunny concert tickets, an annual subscription and bag of sunflower seeds for Yamal.
Alongside a picture of former Leeds winger Raphinha in their shirt, Atletico included the caption: "Don't believe everything you see, especially if it's related to Barca."
"Finally, we want to take this opportunity to categorically deny that we have made an offer to the sporting director of FC Barcelona to join our scouting team in the Brazilian market," another post said, in reference to Barcelona's sporting director Deco.
"No, Atlético de Madrid would never do something like that. However, in recent months, we've been suffering a smear campaign against one of our players.
"Leaked information with ulterior motives, 'fake news,' constant disrespect, the culé (Barcelona) version of the propaganda machine inventing little stories, calls before direct matchups."
Barcelona declined to comment when approached by Sky Sports News. The Spanish FA has also been approached for comment.
Alvarez has scored 20 goals in all competitions in 49 games this season.
