Serie A asked on Tuesday for further investigation into alleged racist chanting from fans during the weekend's stormy Rome derby, won 1-0 by Roma.
In a statement Italy's top flight requested that football federation (FIGC) prosecutors probe chants from both sets of supporters directed at Roma striker Romelu Lukaku and Lazio midfielder Matteo Guendouzi.
Serie A also said it wanted prosecutors to look into "religiously discriminatory" chants from Lazio fans at their Roma counterparts.
The league did not specify the nature of the abuse, but Lazio's "ultras" have a long history of referring to Roma fans as Jewish as an insult.
Lazio have a reputation for having fascist fans but both sets of supporters in the Italian capital have hardcore groups with longstanding ties to extreme right politics.
Serie A also asked for further probes into Roma's match-winner Gianluca Mancini, who after the match celebrated with fans in the stands and waved a flag depicting Lazio supporters as rats.
Italy international Mancini headed the only goal of a tense clash to end Roma's two-year winless run against their local rivals.
In the wild celebrations that followed the final whistle both he and Paulo Dybala, who supplied the cross from which Mancini scored the winner, joined in with chants and waving flags.
Mancini grabbed one flag which depicted a black rat on top of Lazio's colours of white and sky blue, and charged along the running track in front of the Stadio Olimpico's Curva Sud, where Roma's hardcore fans stand.
Mancini's celebrations were a controversial postscript to a typically colourful and tetchy derby in the Italian capital, where passions always run high regardless of what is at stake on the pitch.
Several hundred fans briefly fought near the stadium hours before kick-off before the scrap was broken up by police.
Meanwhile, former Romania defender Stefan Radu, who played for Lazio for 15 years, was pictured at the game wearing clothes with Nazi Germany imagery.
Radu wore a hoody on which Lazio's "S.S." prefix, which stands for "sporting society", was styled as for the World War II-era "Schutzstaffel" paramilitary organisation.
Mancini's winner ensured that Roma would stay fifth in Serie A for another week, five points ahead of Atalanta who lost at Cagliari on Sunday.
Serie A is leading the race for an extra spot in next season's Champions League, meaning a top-five finish could be good enough for Roma to qualify for Europe's top club competition for the first time since 2018.
