Armed police officers unloaded guns from the back of their cars to deal with an incident at Betfred betting shop in Wolverton this afternoon.
It is believed the robbers - who had a knife and the other a firearm - had barged into the Church Street shop in full view of shoppers and demanded money at arround 2pm.
The three men are described as wearing hooded jumpers and dark clothing. No further description of the offenders is currently available.
The previous day, Tuesday, robbers struck at a betting shop in New Bradwell just a mile away.
They threatened staff before stealing cash.
Det Sgt Phil Turner-Robson, of Milton Keynes Force CID, said: “I am appealing for anyone with any information about the robbery or anyone who witnessed the events to speak to police.
“A team of detectives is currently investigating and conducting enquiries in relation to this incident.
“Although the investigation is in its early stage, it is believed to be linked to the robbery of another bookmakers’ shop yesterday in High Street, New Bradwell.
“Officers are conducting extra patrols in the area to provide reassurance and if anyone has any concerns, they should approach an officer.”
If you don’t want to speak directly to the police, contact Crimestoppers anonymously on 0800 555 111.
No personal details are taken, information is not traced or recorded and you will not go to court.