CNN  — 

German football club Schalke has apologized after some of its fans allegedly racially abused Borussia Dortmund’s 15-year-old star Youssoufa Moukoko during an Under-19 match between the two teams on Sunday.

“We can only apologise for the behavior of some of our fans towards Youssoufa Moukoko at today’s U19s match,” the club said in a tweet after the local derby game, using the hashtag ‘NoToRacism.’ Both clubs are based in Germany’s Ruhr region.

It’s unclear what fans may have said.

“Derby emotions aside, we completely condemn and oppose such insults,” added Schalke, which said its Fan Affairs department “will take the necessary measures.”

The Control Committee of the German Football Association (DFB) says it “will examine the possible racist insults” against Moukoko. “The German Football Association does not tolerate any form of racism and goes against any form of it,” said Thomas Bergmann, member of the DFB-Control Committee.

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Youssoufa Moukoko was racially abused by Schalke fans while playing for Dortmund's under-19s.

“The Control committee will investigate if there were racist insults.”

Widely considered one of European football’s most prodigious talents, Moukoko scored all three goals as Dortmund’s Under-19s beat Schalke 3-2 in the local Revierderby.

It was the youngster’s third hat-trick of the season already and Moukoko, who has regularly played several years above his age group throughout his young career, is expected to be called up to Dortmund’s first team when he turns 16 next month.

Born in Cameroon, Moukoko has represented Germany on the international stage with the Under-16s and Under-20s and came through the youth ranks at St. Pauli before transferring to Dortmund’s academy in 2016.

Neither Schalke or Borussia Dortmund were immediately available for comment about Sunday’s incident when contacted by CNN Sport.