Six men have been arrested and released on bail after a series of assaults in St Leonards.
Sussex Police said incidents of violent disorder took place at several locations on Thursday afternoon.
Some people involved had pieces of wood and other makeshift weapons. Two people needed stitches for their injuries.
Insp Mark Bright said the investigation was ongoing and it was anticipated that there would be further arrests in the coming days.
He said officers arrested four local men aged in their 20s, and two men from London, also in their 20s.
Insp Bright said the local men were white and the Londoners black, but he added: "Everything we have established so far indicates that these groups knew each other and that the matter is not related to race. However we are keeping an open mind."
Appealing for witnesses, he said the disorder took place at St Leonards Gardens, a number of local streets including Stockleigh Road and London Road, and at a London Road cafe.
Police have stepped up patrols in the area.