Thousands of pounds worth of power tools were stolen from two vans parked in Sheffield over the weekend.
The vans, which were parked in Driver Street and Furnace Lane, Woodhouse Mill, each had tools worth over £1,500 stored inside.
South Yorkshire Police said vans have become a 'major target' for thieves in the city.
A spokesman said: "If you have a works van or know someone that does please make sure you or they empty it every night as they are a major target."
Anyone with information should call South Yorkshire Police on 101.