An investigation has been launched after posters carrying messages allegedly offensive to retained firefighters were found attached to a fire station.
Gloucestershire County Council has asked police to look into the incident in which posters were pasted inside and outside Tetbury Fire Station in Gloucestershire using industrial strength glue.
The station was not in operation when the damage was done on Sunday night but its retained firefighters were on standby to react to any emergencies in the area.
County councillor Jeremy Hilton said: "These posters were clearly designed to intimidate retained firefighters who remain available to help their local communities.
"The person who put these posters up was also trespassing and causing criminal damage.
"We completely respect the wish of the Fire Brigade Union members to stand on picket lines and publicise their views and hopes for the service.
"But I am extremely disappointed to find that one or two people appear to be resorting to particularly nasty tactics. We will not tolerate this kind of intimidation and have asked the police to rigorously investigate the matter.
A spokeswoman for Gloucestershire Police said: "We received a complaint from the county council relating to criminal damage at Tetbury Fire Station.
"Posters had been stuck up around the station using industrial-strength paste. It is now under investigation and anyone with information is asked to call Cirencester Police."