Three men wearing balaclavas threatened supermarket staff with a baton and a hammer during a robbery in Rugby this morning, February 27.
Staff are said to have been left 'badly shaken' by the incident, which happened at the Tesco Express in Bilton and was first reported to police at 5.30am.
The men stole cash before fleeing.
Detective Inspector Cindy Stephenson from Rugby CID said: "This was a frightening ordeal for the staff who have been left badly shaken by the ordeal.
"I would urge anyone who witnessed the incident or saw anyone acting suspiciously in the area this morning to contact us."
Anyone with information is asked to contact police by calling police on 101 quoting incident 27 of 27 February 2019.
Alternatively, information can be provided anonymously to the independent charity Crimestoppers 0800 555 111.