Atletico Madrid have accused Barcelona and Antoine Griezmann of a "lack of respect" after the Catalan giants' president Josep Maria Bartomeu revealed on Friday that the two clubs had held talks about the signing of the France international.
In a statement, the Liga club confirmed Bartomeu's earlier announcement that there had been a meeting, at Barca's behest, on Thursday to discuss a deal to sign World Cup winner Griezmann, who has a release clause of €120 million (Dh495m) in his contract.
Atletico also said they refused a proposal from Barca that they sign the 28-year-old but delay the payment of the buy-out clause.
"Obviously our response was negative, understanding that both Barcelona and the player have disrespected Atletico Madrid and all its fans," the club said.
The statement also claims that Griezmann had told the club that he had struck a deal with Barcelona in March, just days before the second leg of their Uefa Champions League last-16 tie with Juventus, which saw them dumped out by a Cristiano Ronaldo hat-trick after winning the first leg 2-0 in Madrid.
It added: "Atletico Madrid wants to express is strongest condemnation of the behaviour of both parties, in particular Barcelona, for having induced the player to break his contractual relationship with us during the moment in which the club was not only playing the Champions League tie with Juventus, but also challenging Barcelona for the La Liga title."
Griezmann. who announced in May that he would be leaving Atletico but could not reveal his destination until his release clause dropped from €200 million on July 1, signed for the capital club from Real Sociedad in 2014 and has since scored 133 goals in 257 appearances for Diego Simeone's men.
He has also netted 29 times in 70 international games for France, winning the 2018 World Cup and claiming the Golden Boot at Euro 2016 as Les Bleus lost in the final on home soil to Portugal.
Barcelona won their second straight La Liga title last season but are looking to reinforce their squad after failing again in their bid for a first Champions League triumph since 2015 - suffering a humiliating loss to Liverpool in the semi-finals having won the first leg 3-0.
Barca have also been linked with a possible move to bring Neymar back to Camp Nou.
But Bartomeu admitted there was little prospect of the Brazilian rejoining the club he left in a world-record €222 million transfer to Paris Saint-Germain in 2017.
"We know that Neymar wants to leave PSG, we know it, but we also know that PSG don't want Neymar to leave," he added. "There is no 'Neymar' file."
If Barca can get the Griezmann deal over the line despite the friction it has caused with Atletico, it could also put the futures of former Liverpool forward Philippe Coutinho and teenager Ousmane Dembele in doubt.
Griezmann scored 21 goals in all competitions as Atletico finished second behind Barcelona in La Liga last term, while Dembele and Coutinho managed 11 and 14 respectively.
Bartomeu was speaking ahead of the presentation of rising Dutch star Frenkie de Jong, who has joined the club from Ajax for €75 million.
The 22-year-old midfielder impressed as Ajax won the Eredivisie title and reached the Champions League semi-finals last season.
The Netherlands international said the decision to join Barca "was easy for me".
"They said they had every confidence in me, that they thought I would be a key player for Barca in the future."