Wooden spikes which could seriously injure cyclists have been found on cycle paths in woodland.
Gloucestershire Constabulary say that the traps had been placed in the ground and covered up in Randwick Woods, near Stroud.
As well as the spikes, beer cans had been cut open and placed in holes in the ground before being covered up by bushes.
Police warn that the 'extremely dangerous' traps could not only injure cyclists but also children, walkers and pets, Gloucestershire Live reports.
Issuing a community alert, Stroud PCSO Jayne Fellowes said: "It has been brought to our attention that various hazards have been left on the cycle paths in Randwick woods over the last week or so.
"We have received photographs of the hazards.
"This is incredibly dangerous to all concerned , not just cyclists, but to walkers, children and animals. This is extremely dangerous and unacceptable.
"The items are wooden spikes placed in the ground, beer cans that have been cut open, and large holes dug into the ground and covered with bushes.
"These have now been removed by a good citizen.
"If anyone has seen anyone doing this , please call in and update us with a description of the people.
"All information will be treated in the strictest confidence."