Politicians have condemned footage which shows masked men firing shots over a coffin draped in an Irish tricolour in west Belfast.
Police have launched an investigation after footage of the incident emerged on social media.
It is understood the coffin carried the remains of former IRA man Victor Notarantonio, who died from cancer last week.
Irish-Italian Notarantonio, who was once questioned by Garda about the murder of British agent Denis Donaldson, was buried on Monday.
Mourners gathered outside his west Belfast home on Sunday evening, where the coffin was put on display in the street.
Footage, which appears to have been taken on a mobile phone, captured two masked men firing shots from handguns into the air over the coffin.
The display was followed by an applause.
DUP MP Gregory Campbell said the incident raised serious concerns, adding: “Given recent events, where a police officer almost lost his life as a result of a gun attack in north Belfast, this incident should be a cause for great concern.
“I hope all parties will join with me in totally condemning this display, and I call on anyone who has information about the identities of these gunmen to contact police.”
The UUP’s Jenny Palmer branded the footage “very sinister and alarming”.
She added: “It is a very worrying development and sends shivers down my spine. This sort of thing is totally out of place in today’s society. We are supposed to be moving on from our dark past, but things like this set us back.”
TUV leader Jim Allister claimed the show of strength was “yet more evidence of the sham of decommissioning”.
He added: “Far from the IRA going away we have shots fired over a coffin in a street in Belfast. Where did the weapons and ammunition come from?
“Let’s not forget that decommissioning was supposedly a major requirement before Sinn Fein were permitted to enter the executive.
“Following hard on the heels of the shooting of a police office this is yet further proof of the militancy of republicans at this time.”
Mr Allister also said the incident raised serious questions for the PSNI, and he asked: “Were no officers in the area at the time? If not, why not?”
Alliance’s Stewart Dickson said paramilitary-style displays such as this have “absolutely no place in today’s Northern Ireland”.
“It sends out completely the wrong message to young people and, even worse, puts people at risk,” he added, “This sort of thing is something from our past, not something we want to se in our future.