BUENOS AIRES, Sept. 8 -- Bayer Leverkusen have taken their bid to sign River Plate striker Lucas Alario to world football governing body FIFA.

The Bundesliga outfit announced on August 31 that they reached a deal to sign Alario after invoking the 24-year-old's buyout clause, reportedly set at 19 million euros.

But the Argentine Football Association refused to authorize the transfer after River described the move as "illegal".

"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."

According to River Plate, the transaction breaches FIFA transfer rules, which stipulate that contracts cannot be cancelled when a season has already started.

Alario played in River Plate's 1-0 victory over Temperley in the opening round of the Argentine Superliga season on August 27.