Michy Batshuayi and two other Borussia Dortmund players complained they received racial abuse during their side's Europa League match in Italy on Thursday.

After Dortmund progressed to the last-16 with a 4-3 aggregate win over Atalanta, Batshuayi tweeted: "2018 and still racists monkey noises in the stands ... really ?! Hope you have fun watching the rest of Europa League on TV while we are through." 

The on-loan striker accused the Atalanta fans of making monkey noises for the duration of the match. His teammates Dan-Axel Zagadou and Alexander Isak were also reportedly the target of abuse.

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Dortmund captain Marcel Schmelzer said he was not aware of the noises during the match but that he condemned it "in the strongest possible terms," adding that "this doesn't belong anywhere."

Atalanta were punished as recently as January after Napoli defender Kalidou Koulibaly was subjected to racist abuse during a Serie A match.

Club President Antonio Percassi later apologized. "I'll be honest, I didn't hear them," he said. "If it did happen, then I am very sad and absolutely apologise to Batshuayi. This should never happen."

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European football's governing body UEFA could also investigate Dortmund after their fans set off pyrotechnic flares and aimed a laser-pointer at the pitch.

The game itself ended in a 1-1 draw, which meant Dortmund won the tie on aggregate thanks to their 3-2 victory in the first leg.