THIEVES have stolen 10 scooters in Huddersfield over the last week.
Police say people who own the 50cc machines should beef up their security now.
Sgt John McFadzean, of Huddersfield Community Safety Vehicle Crime Unit, said: "There has been a major upsurge in the theft of these scooters.
"It may be there is a gang going around targeting them.
"They are very light and easy to lift up and put into a van.
"Owners should chain them to something immovable. Putting the steering lock on is not enough," he added.
The thefts have happened across the area, including Marsh, Newsome, Kirkheaton, Marsden, Netherthong and Skelmanthorpe.