Aberdeen have raised a complaint with Uefa after striker Pape Habib Gueye was racially abused by supporters during his side's draw with PAOK Salonika.
The incident occurred during the second half of the 2-2 Europa Conference League draw in Greece, in which the Senegal forward Gueye was a substitute.
Aberdeen say they immediately told the Uefa venue director and met with the match delegate to officially report the incident at full time.
"Pape has the unwavering support of his teammates and all at Aberdeen will liaise fully with Uefa during their investigations into this very serious matter," read a club statement.
"As a club we have zero tolerance for any form of discrimination or racist abuse. There is no place for such behaviour in football, or society as a whole."
Speaking after the game, Aberdeen midfielder Jamie McGrath - who scored the goal that earned the Scottish Premiership side a point - said 24-year-old Gueye was "very upset".
"We're all with Pape," the Irishman said. "We have to gather round him.
"The boys stood up for him, I think Angus was one of them. And I think Rhys [Williams] as well. If we all knew, we might of walked off, I don't know.
"There was that much commotion going on. We didn't have a clue on the pitch we were just focused on the game. All we know is Pape did suffer some form of racist abuse."
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