AC Milan goalkeeper Mike Maignan walked off the field of play 33 minutes into Saturday's Serie A game at Udinese after being racially abused by multiple members of the home crowd.
Maignan informed the referee before leaving the pitch and was followed off by his Milan teammates.
The game was then suspended for around 10 minutes before restarting. Milan went on to win 3-2.
Speaking after the match, Maignan told Sky Sports Italy: "I said we cannot play football like this. It is not the first time it has happened this way.
"They must hand out very strong sanctions, because talking no longer does anything.
"We have to say that what they are doing is wrong. It is not the whole crowd, most fans want to cheer on their team and jeer you. That's normal, but not this."
He added: "What happened in the first half is that at the first goal-kick I heard monkey noises, I said nothing.
"The second time I went to get the ball, I heard it again. I told the fourth official and my bench what happened.
"I was angry, because this isn't the first time it has happened. I did not want to play, but we are a family and I could not leave my teammates like that."
AC Milan later released a short statement via social media. It read: "There is absolutely no place in our game for racism: we are appalled. We are with you, Mike."
Inter Milan replied: "We are brothers of the world, against all forms of discrimination. By your side."
Earlier on Saturday, Coventry City midfielder Kasey Palmer was racially abused during an EFL Championship match at Sheffield Wednesday.
FIFA president Gianni Infantino issued a statement late on Saturday evening.
Infantino said: "The events that took place in Udine and Sheffield on Saturday are totally abhorrent and completely unacceptable. There is no place for racism or any form of discrimination - both in football and in society. The players affected by Saturday’s events have my undivided support.
"We need ALL the relevant stakeholders to take action, starting with education in schools so that future generations understand that this is not part of football or society.
"As well as the three-step process (match stopped, match re-stopped, match abandoned), we have to implement an automatic forfeit for the team whose fans have committed racism and caused the match to be abandoned as well as worldwide stadium bans and criminal charges for racists.
"FIFA and football shows full solidarity to victims of racism and any form of discrimination. Once and for all: No to racism! No to any form of discrimination!"
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