Leeds United and Arsenal have condemned the "vile" abuse aimed at Ezgjan Alioski and Nicolas Pepe on social media after Sunday's stalemate.
Pepe headbutted Alioski in the second half of Sunday's match - which ended 0-0 - leaving referee Antony Taylor no chance but to brandish a red card following a VAR review.
But both clubs were dismayed by the response from individuals on social media reacting to the incident.
A statement from Leeds read: "The vile abuse directed at Ezgjan Alioski and Nicolas Pepe on social media after yesterday's Premier League game with Arsenal will not be tolerated by Leeds United.
"We will work closely with the police and the footballing authorities to ensure those responsible are identified and punished."
Arsenal added: "We utterly condemn the vile abuse directed at Nicolas Pepe and Ezgjan Alioski on social media following our match against Leeds. This is completely unacceptable and we will be working with the police and authorities to do everything we can to trace and prosecute the culprits."
Arsenal manager Mikel Arteta was unhappy with Pepe, the club's record signing, after the game and said his actions were "unacceptable".
Arteta said: "Considering how early we got Pepe sent off we have to take it. I never like a draw but in the circumstances, it's a point. It is unacceptable.
"The first half there were two different periods. The game broke a bit, we started to give the ball away and led to them having the space to break. The second half it was a matter of defending well and staying patient and using the pace of our players in the space they were leaving."
Sky Sports pundit Patrice Evra said he was "disappointed" by Pepe's actions but felt Alioski was looking to get the Ivory Coast international sent off.
"It came from frustration," he said. "You can see early on he was already dealing with Alioski. But Pepe is not happy and it's a little bit silly. He should apologise to his team-mates as Arsenal had a plan and everything changed after that.
"Alioski deserved an Oscar because he played it so well. If I was Leeds' coach, I would be so happy with him. He looked like he broke his nose but he didn't have anything wrong with him. Really, really silly from Pepe. Arteta gave him a chance, so he can't come and cry if he doesn't play the next game."
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