UEFA has opened disciplinary proceedings regarding claims of racial abuse from Manchester City at their victory over Porto in the Europa League.
The governing body will investigate allegations of monkey chants from Porto supporters towards City duo Mario Balotelli and Yaya Toure after the club made a formal complaint.
UEFA said in a statement: "Following a complaint lodged by Manchester City FC, UEFA has opened disciplinary proceedings against FC Porto for the improper conduct of supporters during their UEFA Europa League round of 32 first-leg match against Manchester City FC last week.
"The UEFA control and disciplinary body will deal with the case on March 29."
Porto manager Vitor Pereira has claimed that the Premier League side may have misunderstood the chanting from the Portuguese crowd.