A gang of men armed with a sledgehammer attacked a security van with a guard inside at a garage in Lancashire.
The four men drove into the Texaco garage in Blackburn Road, Haslingden, at about 0600 GMT and started attacking the side of a Loomis van.
The men also went into the garage shop and tried to rob a second security guard, but he managed to secure himself in a separate room and the gang left.
Police said their silver Vauxhall Astra was found abandoned a short time later.
No-one was injured and nothing was taken from the garage.
The scene has been cordoned off by police and an investigation is under way.
Det Insp Nick Hodgeson from Pennine CID said: "I would urge anyone that witnessed any part of this incident or saw anything suspicious in the area around 6am this morning or in the days leading up to the offence to contact police.
"Prior to the security van arriving at the garage, we know the new registration Vauxhall Astra was parked in the car park to the rear of the garage so I would be keen to speak with anyone that saw the men arriving or leaving the scene."