By Q Radio news
Police are studying a video released on social media that shows two gunmen firing automatic assault rifles in Derry/Londonderry.
The incident took place at the unveiling of a plaque remembering INLA member Mickey Devine who was one of ten republicans who died on hunger strike.
The gunmen were applauded by a group of around 30 people.
Social media footage shows a group of masked men and two gunmen carrying automatic assault rifles.
At the command of fire, the two gunmen fired volleys of shots into the air before walking off to applause from a group gathered at a gable wall bearing a mural of Devine.