A man was arrested on Sunday morning in connection with allegations of racist abuse during Saturday's Manchester derby at the Etihad Stadium according to Sky Sports.
United players were subjected to racist taunts from a fan after taking a 2-1 lead at the Etihad with the England Football Association saying that they were investigating the incident.
City on their side said they were "aware of a video circulating on social media" which appeared to show a supporter making monkey gestures towards United players and pledged to issue a lifetime ban to "anyone found guilty of racist abuse".
The incident in question happened when United midfielder Fred went to take a corner in the second half. The 26-year-old Brazilian said it was a shame that such incidents still happen in 2019.
"We are still in a backward society," Fred told ESPN Brazil after the 2-1 win for Manchester United. "Unfortunately, this is happening in some stadiums. It happened here, it happened in Ukraine with some friends.
"It's sad, but we have to keep our heads up and forget about that. We can't give them any attention because that's all they want. I spoke to the referee after the match, they will do something about it and that's all."
Fred also appeared to be hit by an object thrown at Etihad Stadium.