Police say a 15-year-old boy has been arrested for sending a racist tweet to a Manchester United player, widely reported to be Rio Ferdinand, during the stormy derby match against Manchester City.

Greater Manchester Police say the boy was held on suspicion of a racially aggravated public order offence before being released on bail pending further enquiries.

Ferdinand was one of the central figures of Sunday's derby that was marred by crowd disturbances. The defender was left bleeding from a cut above his left eye after being struck by an object thrown from the crowd while he celebrated United's late winner in a 3-2 victory.

A City fan also ran on to the field and toward Ferdinand, but fell and was then obstructed by City goalkeeper Joe Hart.