Six police officers were injured during rioting in Portadown early yesterday.
One of them, a woman, was kicked and punched by a group of men who dragged her to the ground.
Another officer suffered serious facial injuries as more than 100 people rioted. Two men were arrested.
Bottles, bricks and other missiles were thrown when trouble flared in High Street and Edward Street at around 1am.
It was unclear whether the violence was linked to the rioting in Dublin on Saturday.
A Police Service of Northern Ireland spokeswoman said officers managed to separate the crowds in Portadown and push them back. Two police vehicles were damaged and a number of other cars attacked, she added.
A 30-year-old man was charged with disorderly behaviour and assault. He is due to appear at Craigavon Magistrates Court next month.
The second man arrested, aged 34, was released on bail while police carry out further inquiries.
An SDLP MLA for the area, Dolores Kelly, said: "It is completely unacceptable that violence of this nature takes place on our streets.
"It is particularly horrific that a female police officer was assaulted so viciously by a gang of men."