Police have come under attack after stopping a contentious republican parade entering Belfast city centre.
The halting of the anti-internment march in a nationalist area in the north of the city passed off without incident, however, officers were forced to deploy water cannon an hour later when a crowd threw petrol bombs, stones and bottles at them.
The disturbances were sporadic.
The parade had originally been granted permission by the Parades Commission to pass through the city centre, but only before 1.30pm.
The restriction was imposed by the Government-appointed adjudication body to minimise disruption to city life.
In previous years the parade has proceeded through the city.
Last year there were minor disturbances at the controversial event but in 2013 almost 60 police officers were injured when loyalist protesters rioted.
When the 1.30pm deadline passed, the parade had not even left its designated start point in the nationalist Ardoyne area. Police commanders announced that it would be halted.
As loyalist counter protests in the city centre dispersed, police rolled out a huge security operation to stop the march on the Oldpark Road around 2.5 miles away.
Parade participants, including a number of bands, marched up to the police cordon. They held a rally for around 30 minutes, with speeches, cheering and music. At the conclusion organisers urged people to disperse peacefully. The parade turned and went back up the Oldpark Road without incident.
However, an hour later trouble broke out in the area where the parade had been stopped.
The now annual march is organised to mark the introduction of internment without trial by the Stormont administration, with the support of the UK Government, during the height of the Troubles in August 1971.
The controversial policy of detaining terrorist suspects without trial ended in 1975. However, the parade organisers - the Anti-Internment League - allege it is still effectively operated by the state authorities in the present day.
Police made four arrests during the disorder.
Police Service of Northern Ireland assistant chief constable Stephen Martin said: "The aim of the policing operation today was to keep people safe and facilitate the parade and associated protests within the law.
"Due to the parade acting unlawfully, in breach of the Parades Commission determination, police intervened and stopped it on the Oldpark Road.
"After a period of time most people dispersed peacefully but unfortunately some were intent on engaging in disorder and a number of missiles and petrol bombs were thrown at police in the area of Rosapenna Street. Water cannon was used in the area to manage the disorder and a number of officers sustained minor injuries.
"A 53-year-old male was arrested for common assault and disorderly behaviour in College Square East. Two males, 24 and 21 years, were arrested for offences related to the supply of petrol bombs. Police also recovered a container filled with petrol. A 36-year-old female was also arrested for riotous behaviour in the area. All four remain in custody at this time and inquiries are continuing.
"Police will now review the evidence gathered and pursue all relevant lines of inquiry relating to any offences or breaches of the Parades Commission determinations.
"The policing operation will maintain a presence in the area overnight."
Sinn Fein Deputy First Minister Martin McGuinness condemned the parade organisers.
"Those who organised today's so called anti-internment demonstration in Belfast bear full responsibility for the violence which followed," he tweeted.
Northern Ireland Secretary Theresa Villiers said the Parades Commission breach was "totally unacceptable".
"Violence will not be tolerated," she tweeted, also praising the "professionalism and courage" of the PSNI.