Five PSNI officers were injured during rioting in the village of Castlederg, Co Tyrone, last night.
The trouble escalated and up to 50 people were involved in over two-and-a-half hours of disturbances during which bottles and other missiles were thrown at police, said a Police Service of Northern Ireland spokeswoman.
All of the injured officers suffered cuts and bruises and one sustained an eye injury.
One man was arrested for disorderly behaviour, said police.
