Bayer Leverkusen have completed the signing of Velez Sarsfield striker Alejo Sarco, who the Bundesliga champions describe as "a promise for the future".

The 18-year-old has already appeared 20 times for Argentina Under-17s, and makes the move to Germany on a deal that will keep him with Leverkusen until 2029.

Xabi Alonso's side confirmed the move on Thursday, with Sarco keen to impress on the European stage.

"Transferring to a top club in Europe is something I have always dreamed of," Sarco said, as quoted in Leverkusen's official announcement. 

"It's exciting to be a part of the team from now on, and it will be a great challenge for me to support it with my abilities."

His contract expired at Velez on Wednesday, opening the door for him to pen a deal with Leverkusen and join fellow Argentinian, and World Cup winner, Exequiel Palacios at the club.

Sarco caught the eye in the Argentinian League Cup against Estudiantes in May, scoring an equaliser minutes after being introduced as a substitute just past the hour.

"A promise for the future of Bayer Leverkusen," sporting director Simon Rolfes said of Sarco.

"He is a technically skilled player, fast, agile, and assertive in one-on-one situations.

"With his strong finishing ability, he completes the profile of a modern centre-forward."