Robbers threatened staff at a Northampton mini-supermarket before taking goods from the shelves and fleeing.
Three offenders went into the Tesco Express in Link Road, Kingsthorpe, at around 5am today.
A police spokeswoman said staff were threatened but no-one was injured. Officers are still trying to establish what was taken from the store.
The spokeswoman said: “It was still dark at that time of the morning but if anyone was acting suspiciously in the early hours of this morning, or late last night, they should contact police.”
Anyone with information can call police on 101 or Crimestoppers on 0800 555 111.