One visitor said the scenes that confronted bystanders in Edinburgh's George Street were like those from television police drama Taggart.
Eyewitnesses described how a white BMW screeched to a halt and a masked gang armed with an axe, a machete and a hammer leapt from the car and smashed through the Hamilton and Inches store before escaping with a haul of jewellery.
Witnesses said the raid was over in moments. No-one was injured.
Six staff were working at the shop when the robbery took place around 11.30am yesterday.
A police source said it is possible the raiders may have had some "specialist knowledge" because of the way the bladed weapons were swiftly used to smash the display cabinets. Police Scotland were at the incident within minutes and armed response units were thought to have been deployed in the search for the robbers.
A two-car pursuit of the BMW was said to have crossed the city centre eastbound.
A spokesman for Police Scotland said officers are appealing for witnesses and added the escape car was seen driving along George Street, down Howe Street and along Heriot Row.
The car was recovered by police a short time later and is being forensically examined.
One holidaymaker from Denmark, who asked not to be named, described how the robbery unfolded. He said: "Three men came out of a BMW and ran into the shop. They were wearing masks and had a hammer, an axe and a machete.
"We were looking in the shop window. They pushed my wife aside, I took hold of my wife. It was over in a minute or two .We are okay. I don't think anyone was hurt. But they were shocked.
"They were masked and wore dark trousers and they had sneakers on. We see the crime show Taggart in Denmark and when we come to Edinburgh on our first day it is as though we are in a scene from Taggart."
Officers are hunting four people. Detective Inspector Carol Craig, who is in charge of the investigation, said: "We are currently investigating this violent robbery, which put several people in a state of fear and alarm, and I would appeal for anyone who witnessed this incident and has not already spoken to us to contact Police Scotland."
By midday there were eight police vehicles and two ambulances in the street.
Stephen Paterson, managing director of Hamilton and Inches, was reported as saying: "There have been incidents before, but I have never seen anything like this."
Last year, two men who admitted their part in an armed jewellery store raid at Rox In Edinburgh were jailed.
In 90 seconds they grabbed 77 items worth £726,866, including rings, watches and a £100,000 diamond necklace.