Sinn Fein’s criticism of Northern Ireland’s chief constable over the policing of a Troubles commemoration has been blasted by the DUP as “ringing hollow”.

Sinn Fein vice president Michelle O’Neill described “frank” exchanges as she met Simon Byrne and told him of “unprecedented anger” over the arrest of Mark Sykes, a victim of the Sean Graham bookmakers shootings.

However, Arlene Foster expressed concern at Mr Byrne’s public apology issued on Saturday evening along with the suspension of an officer, and described events as having “all the hallmarks of trial by social media”.

The First Minister also stressed that police decisions should be made on law, not politics.

Ms O’Neill said: “I made it clear that the events of last week, both the arrest of a victim laying flowers on the anniversary of the Ormeau Road massacre and the PSNI’s failure to intervene as dozens of masked UVF members roamed the streets have created a crisis in public confidence in policing.

“The stark contrast between the policing operations in East Belfast and on the Ormeau Road has caused considerable anger and I reflected this to Simon Byrne.”

She added: “I left the chief constable in no doubt that the events of recent days are a watershed moment for policing and public confidence in policing.”

Speaking after leading a DUP delegation to meet with Mr Byrne, Mrs Foster said decisions about the matter should have been made at the completion of the Police Ombudsman investigation.

“Given the antics of Sinn Fein at the Storey funeral and their disregard for Covid-19 rules, their criticism of the police rings utterly hollow,” she said.

She also warned that those organising events to mark atrocities from Northern Ireland’s troubled past have a duty to act in compliance with the law.

“While we understand the need for a proportionate and sensitive policing response, operational decisions must be fair and balanced,” she said.

“There should be no apology for enforcing the rule of law.”

Earlier, UUP MLA Mike Nesbitt said the incident on the lower Ormeau Road on Friday was “very unfortunate”, but “no excuse for any politician to use it to question or undermine confidence in the police service”.

On Sunday, Mr Byrne denied being in “anyone’s pocket” as he expressed concern police were being used as a shock absorber in intensifying political clashes.

He also rejected claims commanders had scapegoated two inexperienced officers sanctioned after the arrest of Mr Sykes.

“We have been bashed frankly by recent events and it just seems sometimes that we can’t seem to win,” he said.

The police chief again made clear he had no intention of resigning.

“It’s been a tough week, but I’m not the first chief constable here that’s had to suffer or be accountable… for criticism over the last 50 years,” he said.

There were angry scenes on Friday when police challenged commemoration participants amid suspicions the size of the public gathering breached coronavirus regulations.

Mr Sykes, who was shot several times in the 1992 outrage, was handcuffed and arrested in chaotic exchanges captured on social media.

He was released a short time later.

The conduct of the two sanctioned officers is being examined by the independent watchdog, the NI Police Ombudsman.

The episode followed just days after police officers failed to arrest anyone when they encountered a large gathering of masked loyalists staging an apparent show of strength in east Belfast.

I think it's about resolve and resilience and keeping on our path to be impartial and we're here to uphold the law

The PSNI has also been facing claims of discriminatory policing from loyalists and unionists, who are angry that officers have not intervened when large crowds have gathered for the funerals of former IRA men.

The most high profile of these occurred last June when senior Sinn Fein figures joined hundreds of mourners at the funeral of well-known republican Bobby Storey.

“Sometimes you just feel like we can’t do right for doing wrong,” said Mr Byrne.

He added: “I recognise here that there is often different and competing political views and actually sometimes the police are the shock absorbers of all of that sort of narrative.

“I think it’s about resolve and resilience and keeping on our path to be impartial and we’re here to uphold the law.

“I can’t stop political commentary, nor would I want to, I think it just would be important at the moment for political space, so that my officers and team and staff can carry on with the issues of policing rather than getting involved in the political debate.”

He denied scapegoating the two officers, who only joined the PSNI last July.

“We weren’t influenced by anybody else, we weren’t pandering to criticism or any other inferences,” he said.

“I fully understand some of the accusations but we have to work within due process and actually look at the conduct regime that informs our decisions, sometimes they are not popular but this isn’t about scapegoating, there’s a process that will now take place, we don’t presume what the outcome is.”