Two police officers have been injured during trouble in north Belfast.
They were attacked with bricks by a gang of about 20 youths while on patrol in the mainly nationalist Ardoyne area.
The officers had been on a routine patrol aimed at tackling anti-social behaviour in the area. They had to be taken to hospital for treatment.
Stones and bottles were thrown at police and damage was caused to police vehicles in Ardoyne Avenue. One youth has been arrested, said police.
Inspector Alan Swann said it would take time for the officers to recover.
"Two officers received a mix of head, leg and body injuries which required several stitches to the head and staples throughout their bodies," he said.
"Unfortunately, they will not be able to perform their duties for a while due to these injuries."