Police are investigating an allegation of racist abuse after Manchester City 's Aleksandar Kolarov became involved in a heated exchange with a spectator at St James' Park.
Northumbria Police confirmed they had received a complaint in the wake of City's 3-1 Premier League victory at Newcastle on Saturday.
A spokesman said: "Northumbria Police has received a report of racist language having been used at the St James' Park stadium during the Newcastle United v Manchester City match today.
"Northumbria Police takes such allegations extremely seriously and enquiries are ongoing into the incident.''
It is reported Serbia international Kolarov became involved in a lengthy exchange with a supporter carrying an Albania flag as he warmed up on the sideline during the game.
There is a long history of tension between Serbia and Albania, particularly over the disputed Kosovo region.
Neither club was commenting on the matter on Saturday, although it is reported that Kolarov will be spoken to by police next week.
The defender was introduced as a 37th-minute replacement for the injured Samir Nasri, but was also substituted 18 minutes from time.
Information from the Press Association was used in this report.