Arsenal manager Unai Emery says Granit Xhaka should apologise after he was involved in an angry confrontation with home fans during Sunday's 2-2 draw with Crystal Palace.
The Gunners captain was booed while he walked off the pitch at Emirates Stadium, prompting him to cup his ear.
Emery said: "Yes [he should apologise]. We make mistakes, we need to apologise and we suggested for him to do that.
"Really, he knows he was wrong and he feels inside very deep."
It is not the first time Xhaka has been booed by his own fans this season, with Emery publicly defending the Switzerland midfielder after a game against Aston Villa last month.
That uneasy relationship with the Gunners fans did not stop Emery appointing Xhaka as club captain in September after the summer departure of Laurent Koscielny.
However, Emery has refused to confirm whether Xhaka will remain captain after Sunday's incident.
"At the moment I am not speaking and I don't want to think about that," the Spaniard added.
"It is not easy for him and for the team. We spoke yesterday, and Sunday night also, and this morning.
"He trained normally with the group but he is devastated and sad about the situation."
Xhaka is not in Arsenal's squad for Wednesday's clash with Liverpool, however Emery suggested that was always going to be the case as he makes changes for the game.