Police patrols have been stepped up in two Sheffield suburbs following a spate of burglaries.
Offenders broke into six houses in Arbourthorne and Intake on Wednesday and overnight into Thursday.
Police said all the properties were locked at the time.
Detectives investigating the break-ins believe the offences are all linked, and that they may have been carried out by one or two people.
Cash, jewellery and flat-screen televisions worth several hundred pounds were stolen.
Sergeant Mark Groarke of South Yorkshire Police said: “We believe break-ins have increased because we’re nearing the Christmas period.
“People have ensured their homes are locked, but we’d urge them to be even more vigilant and call us if they see anyone suspicious in the area.
“We’d also ask that people mark their valuable goods so they are more easy to trace if stolen.”
Police have increased patrols in the areas and are checking secondhand shops.