Prosecutors have opened an investigation into alleged racist chants by Lazio supporters directed at AC Milan midfielders Tiemoue Bakayoko and Franck Kessie last weekend, the Italian Football Federation (FIGC) said on Friday.
The chants are alleged to have taken place during Milan's 2-0 Serie A win over Lazio at San Siro on September 12.
Video footage of the incident is being examined after Milan filed a complaint, the statement added.
Bakayoko posted on Instagram, saying: "To some Lazio fans and their racist cries towards to me and my brother [Kessie].
"We are strong and proud of our skin colour.
"I have all my confidence in our club to identify them."
Milan are level on nine points with leaders AS Roma at the top of the league standings, having made a perfect start to their season.
They travel to Juventus on Sunday, while Lazio, seventh in the table, host Cagliari.
Hate Won't Win
Sky Sports is committed to making skysports.com and our channels on social media platforms a place for comment and debate that is free of abuse, hate and profanity.
For more information, please visit: www.skysports.com/againstonlinehate
If you see a reply to Sky Sports posts and/or content with an expression of hate on the basis of race, sex, colour, gender, nationality, ethnicity, disability, religion, sexuality, age or class, please copy the URL to the hateful post and screengrab it and email us here.
Kick It Out reporting racism
Kick It Out is football's equality and inclusion organisation - working throughout the football, educational and community sectors to challenge discrimination, encourage inclusive practices and campaign for positive change.