Lazio's "Curva Nord" terrace will be closed for one match after racist chants at a midweek away game left France international Samuel Umtiti in tears, Italian football authorities said Thursday.
Umtiti left the pitch as he and Lecce teammate Lameck Banda suffered racist abuse from visiting Lazio fans on Wednesday.
The referee stopped the Serie A game in the second half because of racist taunts "coming from the visitor section occupied by Lazio supporters", Italian news agency Ansa said.
The Serie A disciplinary commission said on Thursday the chanting had been widespread.
"Nearly all of the Lazio fans were almost all involved in the repeated racist chants targeting Lecce's Banda and Umtiti," a statement said of around 1,000 visiting fans at the game.
"Those fans gather in the 'Curva Nord' at their Rome stadium and it will be closed for one game," the statement said.
Cameroon-born defender Umtiti, who won the 2018 World Cup with France and is on loan at Lecce from Barcelona, was the primary target of the abuse.
The club insisted their fans are not racist and that the abuse is the work of "a few individuals".
"Lazio condemns the perpetrators of this despicable, shameful and anachronistic gesture and will, as always, offer its maximum collaboration to the authorities in order to identify those responsible," Lazio said in a statement.
"Lazio fans are not racist and cannot be associated with a few individuals who seriously damage the image of the club."
Lecce president Saverio Sticchi Damiani said that the referee halted the game, and that after stadium announcers called for the abuse to stop, "Umtiti asked that the match resume".
The 29-year-old Umtiti left the pitch in tears at the end of the match but also to a standing ovation from the Lecce crowd, according to Italian media.
"He wanted to respond on the pitch to the insults. He reacted like a true champion," newspaper Gazzetta dello Sport quoted Damiani as saying.
Lecce, who won 2-1, afterwards praised their fans for responding to the abuse by chanting Umtiti's name.
"The racist insults were drowned out by the cheers of encouragement for our champion!" the club said on Twitter, along with the hashtag in English #KeepRacismOut.
FIFA president Gianni Infantino also threw his support behind Umtiti and Banda.
"Let's shout it loud and clear: NO TO RACISM! May the huge majority of fans, who are good people, stand up to shut up all the racists once and for all!" he wrote in an Instagram post.
This is by no means the first case of racist abuse in Italian football, particularly among clubs that have connections to the country's far right.
Fascist fan groups are common across Italy. Lazio's ultras group the "Irriducibili" have hardcore supporters with ties to the extreme right that stretch back to at least the 1970s.