Rival groups of migrant workers at a Co Tyrone factory clashed in the street outside their place of work
last night.
Up to 100 people - understood to be from Lithuania and East Timor - fought in the Killyman Road outside the Dungannon plant.
Police called in the quell the trouble said they did not know what the dispute was about, but they arrested one man on suspicion of having an offensive weapon.
One person was treated in hospital for injuries suffered in the clash.
A number of makeshift weapons abandoned in the road when the rival factions ran off were recovered by police.
