GENEVA, Switzerland (AP) — UEFA President Michel Platini has ordered an investigation after a Champions League referee failed to follow guidelines and stop a match to warn Russian fans about racist abuse.

UEFA said on Friday its protocol for match officials to handle racism incidents “was not applied” during the CSKA Moscow-Manchester City match on Wednesday.

“This protocol empowers the referee to stop the match and ask for a public address system announcement to be made urging spectators to stop such racist conduct,” UEFA said in a statement.

Platini’s request puts 33-year-old Romanian referee Ovidiu Hategan under scrutiny, as well as the Russian club.

UEFA has opened a disciplinary case against CSKA, prompted by complaints by Man City midfielder Yaya Toure, who is black.

Toure said he told Hategan during play about monkey noises being targeted at City’s black players by home fans.

“UEFA must take their decision about that,” City coach Manuel Pellegrini said on Friday of Platini’s request. “We did all that we can do here, we can’t do any more.”

Hategan, who has been a FIFA international list referee since 2008, did not stop play and ask stadium officials to broadcast a warning. It is the first step of UEFA’s guidelines to deal with racist abuse in stadiums.

If abuse continues, the second step in UEFA’s protocol empowers referees to suspend a match and take teams off the pitch. The third is abandoning the match.

UEFA said it will publish its investigation findings after the disciplinary case next Wednesday.

Referees have had authority from UEFA since 2009 to halt matches to deal with racist abuse, and the rules received a higher profile ahead of the 2012 European Championship in Poland and Ukraine.

Then, UEFA insisted there was a clear protocol in place after Italy forward Mario Balotelli, who is black, suggested he would walk off the pitch if he was targeted.

CSKA has questioned whether any racially motivated abuse was used, even as it issued a statement on Thursday regretting the incident.

“Having carefully studied the video of the game, we found no racist insults from CSKA supporters to the guests,” the club said.

CSKA has increasing influence in European football through its director Evgeni Giner.

Giner sits on the Platini-chaired UEFA strategy council, as one of four delegates representing European clubs. Giner also sits on UEFA’s club competitions committee which makes key recommendations about running the Champions League.