Tottenham have condemned the "vile, dehumanising racism" aimed at defender Kevin Danso following Saturday's 2-2 draw with Brighton.
Danso was at fault for Georginio Rutter's stoppage-time equaliser which left Spurs languishing in the relegation zone.
The club say they have reported racist abuse towards the Austria centre-back on social media to the police.
"Since yesterday's fixture against Brighton, which took place during the Premier League's No Room For Racism weekend, Kevin Danso has been, and continues to be, subject to significant and abhorrent racist abuse on social media," Spurs said in a club statement.
"We have heard and seen vile, dehumanising racism. Behaviour that is without doubt a criminal offence. It will not be tolerated.
"The club is taking immediate action. We are reporting all identified content to the Metropolitan Police and to the appropriate authorities in the country where perpetrators reside, as well as to relevant social media platforms.
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"We will push for the strongest possible action against each and every person we identify.
"Kevin has our complete and unconditional support as a player and as a person. No one at this club will ever stand alone in the face of this.
"Nothing about form or league position can ever excuse or explain racist abuse. There is no connection between performance on the pitch and the right to target a player with discrimination. Criticism of performances is part of the game. Racism is not."