Residents are being urged to keep their vehicles secure following a number of thefts across Norwich.
Officers have issued the warning after 16 incidents in the past four weeks.
Ten of the stolen vehicles have been motor scooters, motorcycles or mopeds, whilst five cars and a van have also been targeted.
In 13 of the cases the vehicles have been subsequently recovered.
Chief Inspector Nick Paling said: “We appear to have had a number of incidents across the city where vehicles, in particular motorcycles or mopeds, are being targeted by opportunistic thieves.
“Officers are making enquiries regarding these incidents and I would appeal for residents to be vigilant and report any suspicious to police on 101, or dial 999 if you believe a crime is in progress.
“In the meantime, I would urge motorists to ensure they take appropriate measures to ensure their vehicles are secure at all times when left unattended. Make sure you lock car doors and use steering locks on bikes. Where possible, use a garage when parking your car; however, if you do not have access to a garage, try to park in a well-lit place or somewhere that is overlooked.”
For more information on vehicle security, visit www.norfolk.police.uk
Anyone who may have information about the vehicle thefts should contact Norfolk Constabulary on 101 or via Crimestoppers anonymously on 0800 555111.