Masked men have attempted to rob a 'cash in transit' van in the Knockmore Road area of Lisburn.
At about 6am the occupants of the van were approached by three men, one carrying firearm. They demanded cash, however they made off empty-handed.
All three men were wearing balaclavas or scarves around their faces, had hoods up over their heads and were wearing gloves.
One man is described as being of stocky build, wearing a dark-coloured coat and tracksuit bottoms with white stripes down the legs.
The second is said to be of heavy build and wearing light-coloured tracksuit bottoms and top, with a hi-vis bib or vest, open at the front. His top is said to have a small area of white or light coloured writing on the left side of the chest.
The third man was reported to be of a slim to medium build and wearing dark-coloured trousers with a lighter coloured hooded top and a hi-vis bib or vest, open at the front.
It is believed they fled the scene in a silver BMW, which was found abandoned a short time later in the Windermere area.
Police believe they then got into a second car, a grey BMW.
A fourth suspect, the driver, has been described as being of a large, stocky build, around 35 years old with dark, spikey hair, a stubbly grey beard and wearing a dark grey fleece.
Detective Sergeant McIntosh appealed to anyone who may have seen either the silver BMW acting suspiciously in the Knockmore Road area or Windermere area on Thursday morning or the grey BMW leaving the Windermere area, to contact Detectives at Reactive and Organised Crime at Lisburn on the non-emergency number 101, quoting reference 164 of 15/06/17.
Alternatively, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.