Unionists have called for police action over social media footage which appears to show masked men firing shots in the air in Derry city last week.
The incident took place in front of a mural of Irish National Liberation Army (INLA) hunger striker Michael Devine on Friday in the Galliagh area of the city as a plaque commemorating him was unveiled.
One video shows two masked men firing several shots in front of the mural as others watch on.
Devine was one of 10 men who died in the 1981 republican hunger strike in the Maze prison.
DUP leader Sir Jeffrey Donaldson and Secretary of State for Northern Ireland Brandon Lewis both said they had spoken to PSNI Chief Constable Simon Byrne to express their concern over the footage.
Mr Lewis tweeted: “I have spoken with the Chief Constable who has updated me on this incident. These are criminal actions that have no place in today’s Northern Ireland. Anyone with information on these disgraceful scenes should pass it to the PSNI.”
In a social media post, Sir Jeffrey said: “I spoke with the Chief Constable about this disgraceful display of terrorism. He assured me the incident is under active police investigation.
“Colleagues on the Policing Board will be following up on this. No-one involved in such activity is above the law.”
Ulster Unionist leader Doug Beattie said: "Yet again we see masked men on our streets. The PSNI is using the term 'appear to be firearms' as the weapons seem to be gas operated and blank firing, with no empty cases being ejected.
“Also, the sound does not seem to be that of a high-velocity weapon. However, it is difficult to say and the PSNI must conduct a full investigation.
“Regardless of the weapons’ authenticity, there is no place for this in society. These are yesterday’s men, drug dealers, pimps, extortionists and petty criminals.
“Nobody should ever contemplate giving them any kind of support or view them as any kind of freedom fighter. They restrict freedom, they have the boot on the neck of their own community and should be viewed as an embarrassment to nationalism.”
Ulster Unionist councillor Darren Guy added: "The actions witnessed at Fern Park on Friday night should be totally condemned.
“Such deplorable acts should be consigned to the past. It’s disgusting that these types of acts are allowed to continue in Londonderry.
“Glorification of terrorism is always wrong and this INLA ‘show of strength’ is a direct insult to the families of its many innocent victims.”
The PSNI has been approached for comment.