Two police officers were injured after offenders using cloned number plates rammed one of their vehicles.
It happened in the Ilkeston area on the night of January 25.
The Derbyshire Armed Response Unit said one of its vehicles was rammed by a car fitted with cloned number plates that was suspected to be used in crime.
An investigation is underway after the occupants made off on foot.
Two police officers received ‘minor injuries’.
Anyone with information should call 101 quoting reference 1,087.