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 statement added that video footage of the incident, which is alleged to have taken place during Milan's Serie A win over Lazio at San Siro on Sunday, is being examined after Milan filed a complaint.
Bakayoko said himself and Milan teammate Kessie, both of whom are Black, were the targets of derogatory chants from Lazio supporters.
"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," Bakayoko wrote on Instagram after the game.
Ahead of Milan's trip to Juventus on Sunday, coach Stefano Pioli told a news conference: "In regard to the situation with Bakayoko, I am proud to be part of a club that strives to be on the front line against every type of discrimination. We must continue on this path."
Lazio have been hit with numerous stadium bans and fines for racist behaviour from their fanbase in the past.
"It is our moral duty to report any form of discrimination involving our club," Milan CEO Ivan Gazidis said. "We want to once again confirm our commitment to avoid such attitudes in the future, by collaborating with other clubs and institutions to achieve a common goal. Football must be united in protecting our players in a decisive and uncompromising way.
Gazidis added: "Intolerance is not a problem created by football, but it is undoubtedly reflected in football. For this reason, we will continue in our effort to bring about change through football and we are going to launch other initiatives in the coming days."
Milan beat Lazio 2-0 on Sunday to extend their perfect start to Serie A.
Lazio coach Maurizio Sarri was shown a red card after the final whistle as several players, including Zlatan Ibrahimovic and Lucas Leiva, clashed on the pitch. Sarri was then suspended for two matches.
Information from Reuters was included in this report.