Seven police officers have been injured when trouble flared after a loyalist band defied a ruling not to march past a Catholic church.
The Young Conway Volunteers had been banned from parading past St Patrick's Church on Donegall Street, Belfast, after being filmed playing an allegedly sectarian song at the spot during July 12 demonstrations.
The Police Service of Northern Ireland (PSNI) said seven officers were injured after violence broke out in the area as the Shankill Road band marched past the church.
A number of bands played music between Clifton Street and Unity Street area, which police also said was a breach.
One officer was hospitalised in the violence.
It is understood police were attacked when they attempted to keep nationalists opposed to the parade and loyalists apart.
Bottles were thrown from both sides during the trouble.
The Parades Commission imposed the restrictions, which were unsuccessfully challenged in the courts, on the band for the Royal Black Institution march.
Assistant Chief Constable Dave Jones, head of the policing operation, said anyone who defied the ruling will be pursued.
"Today's parade provides challenges to policing and we are fully aware of the impact our actions can have on communities," he said.
"It is important for us that people understand the context in which we are delivering this operation and accept the complexities and challenges with which we are faced.
"Simply, we have to balance the safety of all involved when making our decisions.
"It is our assessment that there have been breaches of the Parades Commission determination and I can assure everyone that we will be working to bring those believed to have breached it before the courts. We have gathered the evidence required to do so.
The Assistant Chief Constable appealed for calm.
In response to the Parades Commission ruling being defied, a spokesperson for the body said its decision was fair and balanced.
"Any breach of the determination will be a matter for the police to investigate and they may refer it to the Public Prosecution Service," the spokesperson said.
"The commission will also take into account any breaches of determinations, or behaviour not in keeping with the code of conduct when considering future parades."
Police said a significant number of people breached the ruling. But they also said the action also constitutes a peaceful protest against the Parades Commission determination.