Bayer Leverkusen have asked FIFA to approve the signing of River Plate striker Lucas Alario after the Argentine Football Association blocked the move.
Leverkusen announced the signing of the 24-year-old forward last month after meeting the Argentina international's release clause from River Plate.
But the AFA has refused to sanction the deal, prompting Leverkusen to ask the world governing body to intervene.
"The Argentinian Football Association [AFA] has refused the release of the player Lucas Alario after consultations with River Plate,'' Leverkusen said in a statement.
"Bayer Leverkusen have absolutely no understanding of the association's and the club's actions. The refusal of the Argentinians to release the player means that Bayer Leverkusen have now requested the registration of Alario as a Bayer player with FIFA.''
Alario's release clause was reportedly set at 19 million euros. The player has travelled to Germany but needs international clearance to play.
Alario scored 31 goals for River Plate in 71 appearances.