UEFA president Michel Platini wants to know why guidelines on dealing with racism were not followed during Wednesday' CSKA Moscow v Manchester city Champions League match.
European football's governing body announced on Friday that Platini wants an internal inquiry on why UEFA guidelines which allow a referee to suspend or abandon a match in the event of racist chants were not adhered to.
UEFA has already charged CSKA Moscow over their fans' behaviour after City's Ivorian midfielder Yaya Toure said he was subjected to racial abuse, and a report into the incident is expected before the end of the month.
But Platini, who has made the fight against racism in the game a major priority, wants to know why the referee allowed play to continue.
Under UEFA's anti-raciksm protocol, in the event of racist chants from fans, the referee should halt the match and issue a call over the public address system for the chants to stop.
If the chanting persists, he should suspend the game and take the players off the field before making a second announcement.
If the chanting resumes once play is restarted, he is expected to abandon the game.
UEFA intend to make the results of the internal inquiry public, once the initial disciplinary report has been published.
Toure described as "unbelievable and very, very sad" the monkey chants reportedly directed at him by fans of the Russian capital club during the game, won 2-1 by City.
"We want to stop that and UEFA have to be strong, maybe close the stadium," Toure told Britain's Sky television at the end of the match.
Toure later said he did not exclude the possibilty of black players boycotting the 2018 World Cup in Russia as a result of their treatment at the hands of Russian fans.