A 16-year-old has been arrested on on suspicion of arson in connection with a massive mountain fire.
Fire crews were called to the blaze in Blaenau Ffestiniog, Gwynedd, at about 20:30 BST on Monday and about 20 homes had to be evacuated as flames spread.
The teenager was also arrested on suspicion of causing a public nuisance and assaulting a police officer.
They are in custody. North Wales Police also said a man had been arrested for obstructing a police officer.
Insp Matt Geddes said: "The fire is being investigated as a deliberate and criminal act which put a number of family homes and businesses at risk, and caused the evacuation of tens of properties."
Firefighters remain at the scene of another fire in nearby Beddgelert.
Gavin Roberts from North Wales Fire and Rescue Service said: "Deliberate grass fires put lives in danger - this incident tied up valuable resources for a considerable length of time, putting not only our firefighters but also local residents at risk."