Masked men, one armed with a handgun, threatened a member of staff during a robbery in at a bookmakers in Londonderry on Friday evening.
It is understood to have been the fourth such incident in the area in recent days.
Two men, wearing ski masks to cover their faces, entered the shop in Central Drive in Creggan at around 8.30pm and made off with money.
One of the males is described as being 5ft 8ins tall and was wearing a black leather jacket.
The other man, who was described as being slightly taller, was wearing a padded coat.
SDLP Foyle MLA Mark Durkan urged people to be vigilant following the incident.
“I want to condemn those behind a robbery at the bookies at Central Drive in Creggan yesterday evening who subjected staff to a terrifying ordeal.
“This is the fourth such robbery in recent days at bookies shops in the area and is a worrying development. This must have been a very traumatic experience for staff who have been working hard over the Christmas break.
“I would urge bookies and other businesses to exercise vigilance and be mindful of security arrangements particularly at this time of year.
“Anyone with information regarding these robberies should come forward to the PSNI as a matter of urgency.”
Detectives in Strand Road have appealed for information.