Pictures of three cars and a van have been released after they were said to be acting suspiciously in countryside backwaters.
Renfrewshire Rural Watch published the images, warning people to keep an eye out.
Though there is no evidence of criminal activity, the group says the vehicles triggered rural radar.
Renfrewshire Rural Watch said: “These vehicles have been seen acting in a suspicious manner in the Houston and Kilmacolm areas recently.
“Please be aware of any cars left in unusual areas or if occupied and they are observing property.
“Help prevent rural crime and report your concerns to the police by dialling 101 with details of the location.”
The cars at the centre of the alert are a Mitsubishi Shogun Sport, a Toyota Prius, Ford Transit and a Fiat Panda.
Renfrewshire Rural Watch was set up to make rural Renfrewshire secure against illegal activity such as the theft of machinery, equipment, livestock, metal, poaching and fly-tipping.
They are supported by Police Scotland, Scottish Land and Estates and the Scottish Countryside Alliance.
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