Shots were fired at a police car in the early hours of Friday, police said.
Two shots were fired at the police patrol car as officers made a routine stop-check on a vehicle at around 4.10am, on a road leading on to the M5 motorway in Gloucestershire.
A spokeswoman for Gloucestershire police said a patrol car had stopped to make a routine check on a blue L-registration BMW 3 series that was parked in a lay-by on the B4008, just off junction 12 of the motorway near Gloucester.
But, as police pulled up behind the BMW, two shots were fired from the vehicle.
Gloucestershire police spokeswoman Kate Nelmes said: "As police pulled up behind the vehicle, it made off on to the south-bound carriageway of the motorway and two shots were fired from the BMW in the direction of the police vehicle."
She added that no one was hurt and that the BMW sped off down the south-bound carriageway of the M5.
Police closed the motorway in both directions between junctions 12 and 13.
The B4008 from junction 12 of the M5 towards Stonehouse has also been closed as police search the area.
Neither of the shots fired from the BMW are believed to have hit the patrol car, police later confirmed.
A police spokeswoman said there were "at least two and possibly three people" in the BMW at the time of the shooting. Police could not confirm at this stage what type of weapon had been used.
