THREE speed cameras have been targeted by arsonists.
An investigation has been launched following the series of attacks, which police believe to be linked.
Car tyres and rubbish have been used to start the fires.
The first camera was targeted shortly before 6.30am on Tuesday in Pentre, near Deeside.
Yesterday another two were set alight half-an-hour apart.
Just before midnight on the A5119 in Sychdyn, near Mold, a car tyre was placed on top of the device to assist the blaze.
At 12.30pm the speed camera on Chester Road, Sandycroft was also set alight, after rubbish was placed around it.
North Wales Police said they are treating the incidents as linked and working with the fire service and the arson reduction team.
Insp Ceri Hawe said: “The cameras are there to ensure the safety of motorists, cyclists and pedestrians and deliberate attempts to damage them will not be tolerated.
“Anyone with information about these criminal acts should call the police.”
Kevin Jones, arson reduction manager said deliberate fire-setting incidents put “extra pressure” on fire and rescue resources and place crews and the public at “extra risk”.
He added: “Of course, whilst crews are busy dealing with these incidents they would not be able to meet what may be a real need for them to attend a life-threatening situation elsewhere in the county.
“Deliberate fires are a serious crime and in conjunction with North Wales Police we will pursue convictions. I would therefore appeal to anyone with information on such activities to report it to police.”
Anyone with information in relation to deliberate fire-setting is urged to contact North Wales Police on 101 or anonymously via Crime stoppers on 0800 555 111.