An investigation is under way into rioting in County Armagh in which six police officers were injured.
One officer suffered serious facial injuries in violence involving up to 100 people in Portadown.
The trouble began at about 0100 GMT on Sunday when the crowd threw bricks and bottles.
Upper Bann MP David Simpson condemned the violence. But he said that there were more positive things happening in Portadown than there are negative.
"A lot of reports will come out that it was one set or the other that started it and it was a spin off from Dublin. We don't know that," he said.
"The reports coming back from the PSNI may be able to put some light on that."
"What has happened, has happened. It should not have, but it did."
Bricks and bottles were thrown at police during the trouble.
At one stage, a group of men attacked a woman police officer and forced her to the ground before kicking and punching her.
A 30-year-old man has been charged with assault and disorderly behaviour. He is due to appear before Craigavon Magistrates Court next month.
Meanwhile, a 34-year-old man has been released on bail pending further police inquiries.