Violent clashes after Grimsby-Scunthorpe derby
Six people were arrested as violence erupted between fans after the Grimsby Town and Scunthorpe United derby match.
Six arrests were also made before and during the FA Cup game at Blundell Park, which was the first clash between the local rivals in five years.
Those arrests were for pitch invasions, breaches of football banning orders and public order offences.
However, police pointed out that the "overwhelming majority" of the 8,000-strong crowd caused no trouble.
Humberside Police said they were pleased that a game "of great significance for both sets of supporters" was not spoilt for most fans.
Supt Dave Hall said: "Following the match, as police made attempts to direct Scunthorpe United fans safely away from Blundell Park, an altercation took place between a large number of individuals.
"These people are believed to have been both Grimsby Town and Scunthorpe United supporters.
"One person sustained injuries in the incident and left the location before receiving any treatment.
"A further six arrests were made following this altercation and these people remain in police custody at Grimsby police station."
The 1st round tie finished 0-0.