Schalke sporting executive Christian Heidel has responded angrily after Bayern Munich declared their interest in signing Germany international Leon Goretzka.

Goretzka, 22, is only under contract until June and has been linked with clubs including Real Madrid, Barcelona and Liverpool, but Bayern are widely reported to be leading the race for his services.

On Wednesday, Bayern sporting director Hasan Salihamidzic said "Goretzka is a great player" and added: "He is a Schalke player and we obviously respect that, but he is a Germany international and we can say that we are interested in him."

Heidel has responded by labelling Salihamidzic's comments "unnecessary," telling reporters: "We do not want any unrest at Schalke.

"Bayern insist Leon is a Schalke player but still talk about a Schalke player more than they do any of their own.

"This way speculation is fuelled. We should not have to listen to [Bayern] Munich telling us every day how good the player is."

Leon Goretzka is currently taking part in Schalke's training camp in Benidorm, Spain. TF-Images/TF-Images via Getty Images

Goretzka, who has helped Schalke to reach the winter break in second place in the Bundesliga, has been linked with Bayern since helping Germany win the Confederations Cup in Russia last summer.

Sport Bild claimed in May that he had already agreed to join the Bundesliga champions -- a report immediately denied by the midfielder on his Facebook page.

Goretzka's agent, Jorg Neubauer, this week denied reports that the midfielder has already agreed to move to Bayern, assuring Heidel by telephone that the player is yet to make a decision on his future.

However, respected German publication kicker reported on Thursday that Goretzka is almost certain to join Bayern provided he passes a medical.