Arsonists who set fire to four wheelie bins in Flintshire on Tuesday evening are being hunted by police.
North Wales Police said three fire engines attended the incidents at Flint Mountain following a call at 8.50pm.
Nobody was injured as a result of the fires, which police believe are linked.
A joint investigation has now been launched between North Wales Police and North Wales Fire and Rescue Service.
A statement on the police force's North Flintshire Facebook page said: "Police officers have increased patrols in the area in a bid to reassure the public and we are asking everyone to be vigilant and to report any suspicious activity."
Anyone with information is urged to contact North Wales Police on 101, reference Y155164.
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