Undercover police officers are being used to try to catch thieves targeting vans in Sheffield.
They are hoping to catch offenders in the act.
Officers in uniform are also patrolling the streets in a bid to deter thieves.
Inspector Jason Booth, of the Sheffield South East Local Policing Team, said: "We continue to see vans and commercial vehicles broken into in the south east.
"The method is usually the same by forcing the rear doors. I can't say its one particular type of van, it's across almost all the manufacturers. The crime is also across the entire area but pretty much always overnight with tools being the items stolen.
"We have put messages out previously about trying to remove valuables where you can but what we need to do is catch those responsible and put a stop to it.
"We know that often the thefts affect people's businesses and ability to work. It's always worth marking any tools with some form of permanent identification, ideally a postcode and house number.
"We will continue to do what we can with uniformed and plain clothes patrols into the night but anything you can do to help us in our efforts locally will be appreciated."
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.