Middlesbrough are to investigate an alleged racist incident in their 2-1 victory at Leicester City on Saturday.
Footage has emerged on social media of an incident in the away end.
The Teesside club said they have zero tolerance towards racism and that they would work to identify those involved.
"We have a zero-tolerance approach towards racism and all forms of discriminatory behaviour and will take the strongest action possible," the Championship club said in a statement.
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