Police are dealing with an incident near HMP Walton and have closed off nearby Aintree Road.
Visits to the prison have reportedly been cancelled.
And cops have confirmed that an investigation is under way.
A statement reads: “Officers attended and found damage to a grey Renault Megane car consistent with a firearm discharge.
“There have been no reports of anyone injured during the incident.
“It is believed three to four offenders ran from the scene on foot in the direction of Hornby Close before getting into a black Audi car before driving away.
“A number of bullet casings have been recovered from the scene and taken for forensic examination.
“A cordon is in place while Crime Scene Investigators carry out forensic examinations at the scene and house-to-house enquiries are underway.
“High visibility patrols will be stepped up in the area and CCTV opportunities in the area will be explored.”