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.
- Summer window opens on June 15 and closes on September 1
- Transfer Centre LIVE! | Latest on YOUR PL club!
- Download the Sky Sports app for expert analysis, best video & more
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.
(c) Sky Sports 2026: Atletico Madrid accuse Barcelona of 'smear campaign' over potential bid for Julian Alvarez this summer
Arsenal ready to take shot at immortality in Champions League final against PSG but which side has the edge?
Novak Djokovic says he doesn't know if he will return to play at the French Open next year, after losing to Joao Fonseca
PGA Tour: England's Jordan Smith leads at Charles Schwab Challenge with Hideki Matsuyama and JJ Spaun keeping pace
Vaibhav Sooryavanshi: Teenage wonderkid becomes second fastest player to reach 1,000 IPL runs but falls short of century