Borussia Dortmund have told Barcelona that Ousmane Dembele is not for sale this summer amid reports the Catalan club have held talks with the player's agent.
Barca sporting director Robert Fernandez said this week the club will make some "big-name signings" this summer and Dembele's name has been frequently linked with a move to Camp Nou.
However, Dortmund's sporting director Michael Zorc says Dembele is firmly part of new coach Peter Bosz's plans for next season.
"Ousmane Dembele has a long-term contract [until 2021] and we are making definite plans with him," Zorc told German newspaper Waz.
"There are no negotiations [with Barca]. Ousmane is going to be playing for Dortmund in the coming season."
Dortmund signed Dembele from Rennes last summer for €12 million and the player himself has since confirmed that Barca made a move for him at the same time.
"Last year, I did have contact with the Barcelona sporting director," he admitted, after scoring the winning goal in France's recent 3-2 win over England.
"But I'm feeling good in Dortmund. I have a contract until 2021 and I'm not paying attention to what is being said [about the future]."
Waz even suggest Dortmund could consider reporting Barca to FIFA were they to learn they had contacted Dembele without going through them first.
In a similar case earlier this month, Southampton are reported to have asked the Premier League to investigate an alleged illegal approach from Liverpool for Virgil van Dijk, prompting the Reds to release an official apology.