Inter Milan have been ordered to play their next two Serie A games behind closed doors, and close part of the stadium for one further game following the racial abuse aimed at Napoli's Kalidou Koulibaly on Boxing Day.

Serie A announced that no spectators will be admitted to the Nerazzurri's next two games against Sassuolo on Jan. 19 and Bologna on Feb. 3 in response to Wednesday's incidents, which it says were not isolated.

Meanwhile, Koulibaly has been banned for two games for the red card he received in the 81st minute of the game, as a result of the second yellow he received "for applauding the official in an ironic manner, having already been booked."

As Koulibaly was being shown the cards, monkey chants were clearly audible from a significant number of fans inside San Siro, with further chanting as Koulibaly left the field.

After he was dismissed, his teammates tried to explain to referee Paolo Mazzoleni that the 27-year-old defender's reaction was aimed more at the fans than at the official.

"I am only sorry for the defeat and above all to have left my brothers," Koulibaly wrote on Instagram after the match. "But I am proud of the colour of my skin; to be French, Senegalese, Neapolitan: a man."

Napoli coach Carlo Ancelotti said he had asked the fourth official to halt the game three times, but apart from stadium announcements being made, no further action was taken. He added that the next time it happens, he will just take his team off the field, even if they risk conceding the game.

Inter released a statement on Instagram and Twitter on Thursday condemning the racist chants, while adding that discrimination of any kind has no place in the club or from their supporters.

Since 1908, Inter has represented integration, innovation and progressiveness. The history of Milan is a welcoming one and together we are fighting to build a future without discrimination. Those who do not understand this history do not stand with us. #BrothersOfTheWorld #FCIM pic.twitter.com/lUok3qDgno — Inter (@Inter_en) December 27, 2018

Napoli captain Lorenzo Insigne will also miss two games for the red card he received deep in stoppage time "for aiming a seriously insulting remark at the referee," with his sanction more severe in view of the fact he was wearing the captain's armband.

Saturday's games in Serie A will go ahead in spite of the incidents, which overshadowed Inter's fixture with Napoli as well as the death of an Inter fan in clashes between rival fans ahead of the fixture.

Two arrests have been made, and the police are seeking a third suspect as the fan, identified by police as 35-year-old Daniele Belardinelli, was killed after being hit by a van close to the San Siro on Wednesday night.

Belardinelli was struck after a group of Inter ultras had stopped and attacked a van of Napoli supporters on their way to the stadium around an hour before kick-off.

The Napoli fans got out of the van and fought back, with several receiving knife wounds, before getting back into the vehicle on Via Novara -- one of the main roads toward San Siro -- and driving off, knocking down the Inter fan on their way.

He was taken to the city's San Carlo hospital, where he underwent emergency surgery on Wednesday night. However, doctors were unable to save his life and he was pronounced dead on Thursday morning.