Four masked men have raided the Waterdale branch of the Credit Union before speeding off in a getaway car.
Women were heard screaming in terror as the balaclava-clad men burst into the Queensgate branch at about 9.30am yesterday.
Five members of staff and five members of the public, including three children, were in the store as the robbers made threats.
They made off with at least one bag containing several thousands pounds, jumped into a black VW Golf and screeched away down College Road.
They were last seen heading towards Balby.
An eye witness said: “I heard a woman in distress, very distressed. I thought maybe she was getting punched or it was an argument.
“As I was approaching Iceland there were three or four men running out (of the Credit Union) wearing balaclavas.
“They were dressed in black and they came flying out of the shop and turned to their right hand side. They all came flying out of the door together.
“I remember one of them had a big bag. Obviously that contained whatever they decided to take and they scarpered off.
“The woman was still screaming and later on the police car came.”
The Credit Union was closed for the day and police tape was put around the building.
A South Yorkshire Police spokesman said: “We got the call at around 9.45am to say three offenders, believed to be male, had come into the South Yorkshire Credit Union on Queensgate in the Waterdale Centre.
“The three offenders were armed with an electric stun gun and they threatened the staff, who were made to hand over several thousand pounds from the counter.
“They were wearing dark clothing with masks covering their faces.”
The spokesman said officers were exploring the possibility that the robbery is linked to a similar incident at the Goldthorpe branch last Tuesday, where two men brandishing a baseball bat and a knife stole a quantity of cash.
A spokesman from the credit union said he believed the Goldthorpe robbery encouraged a ‘copycat’ crime but he did not wish to comment further.
A businesswoman who works nearby said: “At the end of the day, people are hard up. It doesn’t matter if you’re here or down on Oxford Street in London - these things happen everywhere.
“I just hope that no one was hurt. It will really have shaken up the girls who work there.”
Police are appealing for witnesses. Anyone who has any information or who has come across any discarded dark-coloured clothing should call 101 and quote incident number 262 of July 22.