Deputy First Minister Michelle O'Neill has requested an urgent meeting with the PSNI Chief Constable after police arrested a victim of a Troubles shooting during an anniversary event.
Mark Sykes was detained in the Ormeau Road area of Belfast after officers intervened at the memorial marking the 29th anniversary of a loyalist massacre at the Sean Graham's bookmakers shop, his lawyer said.
Public gatherings of more than six people are currently prevented under Covid-19 lockdown regulations in Northern Ireland.
Five people, including a 15-year-old boy, were murdered and several others injured in February 1992 when Ulster Freedom Fighters (UFF) opened fire at the bookies.
Footage of angry exchanges involving officers and those attending Friday's event have been posted online.
Mr Sykes was later released from Musgrave PSNI station in Belfast.
Chief Constable Simon Byrne appealed for calm following the incident and in a statement issued on Friday evening he acknowledged that it had taken place on what was a "difficult day" for the families involved.
Mrs O’Neill said in a statement on Friday evening that she requested the urgent meeting with Mr Byrne "to discuss the response to the awful scenes in Belfast today".
“The man was arrested at an event to commemorate the 29th anniversary of the Massacre, in which five people including a child were killed by loyalist gunmen using weapons brought into Ireland by a British agent," she explained.
“The arrest by the PSNI of this man who was at a wreath laying ceremony attended by family members of those killed has caused unprecedented anger and distress across the community."
She added: "The PSNI’s response tonight is inadequate. It further adds insult to injury to the families of the victims who have been waiting almost three decades for truth about the deaths of their loved ones.
“I have also contacted the families and am seeking to meet with them as soon as possible.
“The Chief Constable needs to understand the damage that the actions of his officers today has had on community confidence in policing."
The Sinn Fein vice president continued: “This standard of policing is not acceptable and should not be acceptable to any section of this community.”
Mr Byrne said footage of the incident, including body cam footage, will be reviewed.
Outside the police station earlier Mr Sykes' lawyer Niall Murphy said: "Every year the victims and survivors gather in dignity to remember their loved ones and to say a short prayer.
"This year because of Covid restrictions it was restricted to the five families who maintained a dignified silence and left flowers down.
"The police attended, for what reason I will never know, approached victims and survivors of an atrocity and commenced to harass, push and assault man, woman and child."
Mr Murphy said his client was arrested on suspicion of disorderly behaviour.
"The only disorderly behaviour that happened on the Ormeau Road today was by the police who had no right to be there and who have wreaked havoc on community relations both in the Ormeau Road and in the wider community," he said.
Sinn Fein Policing Board member Gerry Kelly said he was "shocked and appalled" at the man's arrest.
He accused police of "heavy handed" tactics.
"The man and other relatives of the five victims of the massacre, which included a 15-year-old boy, were laying wreaths at the scene of the murders to mark the 29th anniversary of the slaying of their loved ones," he said.
Mr Kelly said family members had gathered to call for the publication of a delayed police ombudsman's report into the murders, amid allegations of state collusion.
"As the relatives were dispersing police moved in and arrested a victim of the Bookies' Massacre," he said.
Mr Kelly added: "This man should be released immediately and the police should apologise for adding insult to injury to the families of those who lost their lives in the massacre and who have waited almost 30 years for truth and justice."
Mr Byrne said in a statement on Friday evening officers from the South Belfast Local Team came across a group of "between 30 and 40 people" at the memorial event.
"As the event concluded, two officers approached a person to talk to him about a breach of the Health Protection Regulations," he explained.
"The situation quickly escalated and a man was arrested for disorderly behaviour and resisting arrest. He was taken to Musgrave Police Station and was released at 4.04pm. In the course of the incident a police officer sustained a minor injury to his face."
The senior police chief added: "We are now reviewing all footage of the incident including our officers Body Worn Video and have notified the Office of the Police Ombudsman, and we are carrying out an assessment of the conduct of the officers involved.
"I have personally spoken to the First Minister, the Deputy First Minister, the local Member for Parliament and a range of other stakeholders to brief them on what has happened."
Mr Byrne added: "I fully recognise the sensitivities of this incident and just how difficult a day this would have already been for the families who lost loved ones in the atrocity. That should not be forgotten.
"We are acutely aware that this is the latest incident to raise concerns about the enforcement of Coronavirus Regulations and illustrates there are no easy answers. I would appeal for calm at this time."