A police officer needed hospital treatment after being injured during clashes between rival mobs in running street battles in north Belfast.
The security forces moved in to saturate the Limestone Road, the scene of almost nightly sectarian violence between Protestant and Catholic youths.
A Police Service of Northern Ireland (PSNI) spokesman said a number of officers were injured by missiles as the fighting continued for about an hour, and one was taken to hospital.
He said: "As the trouble escalated, police fired one plastic baton round as they were attacked by a barrage of bricks, bottles and masonry."
Loyalist community leaders accused the police of heavy handedness, claiming that officers had fired five plastic baton rounds as they chased rioters into the Tiger's Bay area.
They also claimed a number of people had received head injuries after riot squad officers batoned them to the ground.
Mr Alfie McCrory, a community worker from the Shankill area, who had come to the Limestone Road to observe the trouble, said one woman was struck by a baton as she videoed police swamping the area.
"I don't condone what is going on here but when a girl was using a video camera they (the police) cracked her on the head," he said.
Sinn Fein councillor Mr Eoin O'Brion said the latest wave of violence began when a loyalist mob attacked Catholic houses in Park End Street.
He called for talks to end the unrest.
PA