Police said they were called to reports of anti-social behaviour in Leyland on Monday (October 11) and Tuesday (October 12).
It was reported a group of youths had been caught climbing onto the roof of the B&M store in Churchill Way.
The group had also allegedly threatened members of staff at the nearby McDonald's restaurant.
A spokesman for Lancashire Police said: "We arrived and spoke to staff and reassured them that we are now going to check in with the stores on a regular basis to try and prevent this happening all the time."
Officers have urged anyone having problems with anti-social behaviour to call 101 or report it online at doitonline.lancashire.police.uk.
Police said there was also help and advice available on their website HERE.
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