Police are investigating the circumstances around a brawl which erupted during a Belfast city centre parade.
The Pride of Ardoyne flute band said it was forced to defend its colours, blaming thugs for attempting to rip down a bannerette.
One man, aged in his 30s, received a head injury although did not require medical assistance after trouble broke out in the High Street area on Saturday evening.
Police also said that while they were attending the scene, a man in his 70s collapsed and was taken away in an ambulance.
Eyewitnesses said at one stage between 30 or 40 people were involved.
At one point - in video footage shot by an eyewitness - one man can be seen hitting another with a loud crack heard before he walks away. The injured man can be seen holding his head before dropping to the ground.
Witnesses also said tourists got caught up in the melee.
The parade was stopped for around 10 minutes as bandsmen, members of the Royal Black Institution and police worked to calm tensions.
Shocked onlookers were drawn out into the street as the incident unfolded. The Pride of Ardoyne flute band, in a Facebook post, said questions needed to be asked over the police response time.
"Again the Pride of Ardoyne will not be demonised by the media for defending themselves from attack but with no condemnation of those who attacked a peaceful parade.
"We, the POA, will continue to walk the queen's highway, remain loyal to the crown and hold our heads up high as we do so."
The incident broke out as the return feeder parade made its way back from a Royal Black Institution 'Last Saturday' demonstration in Holywood.
The Royal Black Institution said it was aware of an incident saying several members of the public charged into the flute band in an "unprovoked attack" targeting standard bearers. It said none of its members were involved and appeal for co-operation with the police.
Superintendent Lorraine Dobson, who was silver commander for the Belfast parades, said officers attended and spoke with a number of people and took their details.
"The disturbance is reported to have occurred as a band parade was passing through the area," she said.
"Officers made their way on foot through the crowds of band members and spectators. Once at the scene we spoke with a number of people and recorded their details. Additional resources were sent to the scene but were not required as the incident ended quickly.
"It was reported a man, aged in his 30s, had sustained an injury to his head but did not require medical assistance at the time.
"Whilst the police were in attendance, a man in his 70s collapsed and was taken away from the scene by ambulance."
She added: "Our enquiries to establish exactly what occurred are continuing and I would appeal to anyone who saw what happened, or anyone who can assist us with our investigation, to call 101, quoting reference 1493 of 31/08/19.
"Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111, which is 100% anonymous and gives people the power to speak up and stop crime."