Two men have stolen cash from a Sainsbury's petrol station in Grantham.
The offenders were dressed in dark clothing with scarves covering their faces during the robbery last night.
Police were called to the London Road petrol station just after 10pm.
Witnesses are being urged to come forward. Officers also want to speak to anyone who saw men fitting the descriptions in the area.
To contact police, call 101, quoting incident 468 of February 1.
Alternatively, call Crimestoppers anonymously on 0800 555 111.