Nationalist residents from the Garvaghy Road area of Portadown have rejected the RUC's version of events in the Woodhouse Street area last night.
The RUC say they were called to the town centre to deal with fighting between rival factions.
But the Garvaghy residents say the trouble started when 30 loyalists attacked a Catholic-owned pub around 7 o'clock.
A young Catholic man was injured in the incident.
They said that as the man was being treated at the scene, loyalists chanted slogans about the murder of Robert Hamill.