Antoine Griezmann's contentious move to Barcelona looks set to get even uglier after his former club, Altetico Madrid, requested La Liga block the French forward's transfer as the two clubs continue to dispute over the fee. World Cup winner Griezmann signed for Barcelona earlier this month for €120 million (Dh491m) after the Spanish giants triggered the buyout clause in his Atletico contract. However, Atletico are insisting Barca did not pay enough. The buyout clause had dropped from €200m to 120m on July 1, but Atletico claim that Griezmann's May 14 announcement that he was leaving the club is proof a deal was struck between the player and Barcelona much earlier. Atletico had previously accused Barcelona of approaching Griezmann behind their back, and have now taken their issues to the Spanish league authorities. "[Atletico] submitted a complaint and put in doubt whether we should pass Griezmann's licence to Barcelona," La Liga president Javier Tebas told Spanish radio station Onda Cero on Wednesday. "There's a process that has been put in motion and those overseeing it will have to come to resolve the case. "It is possible to block a player's transfer. La Liga will have to decide what course of action to take." Griezmann has already played a friendly for his new club, a 2-1 defeat by Chelsea in Japan on Tuesday. Barcelona have spent approximately €235m on new players so far this summer, including the €75m capture of Dutch midfielder Frenkie De Jong from Ajax.