Police were attacked with missiles in Banbridge, Co Down, when a crowd turned on them after a nightclub closed early today.
Around 30 people were involved in serious disorder and started fighting in the centre of the town after the club closed at around 1.30 a.m.
They attacked police with missiles and hurled abuse when officers moved in to quell the trouble.
No police were injured but two men, aged 21 and 23, were arrested for disorderly behaviour.
Police said a short time later they were called to the car park of a nearby hotel after a report of three people being injured in a hit-and-run.
One person was taken to hospital after being struck by a red Nissan and two more were treated at the scene by ambulance staff.
A 17-year-old youth was arrested for motoring offences when the red car was stopped by police.