Two fires which are thought to have been started deliberately on the same housing estate within a few minutes of each other are being investigated.
Fire crews were called to the area of Atherton twice in the space of just three minutes in the early hours of Thursday morning.
The first incident at 12.04am involved two cars being set alight on a car park on Chaucer Grove.
Then, at 12.06am, fire engines attended a property just a couple of streets away on Cowper Avenue as the dining room of a ground-floor property was on fire.
Greater Manchester Police (GMP) said two people were seen running away from the scene on Chaucer Grove.
The fire service said a Volvo saloon and a Toyota Yaris were torched in the parking area to the back of a property.
Three fire crews tackled the blaze in the house on Cowper Avenue, where a man was treated for minor effects of smoke inhalation.
He did not go to hospital.
Three fire engines from Atherton, Bolton Central and Leigh attended and extinguished the flames before passing the incident over to GMP as a possible case of deliberate ignition.
GMP confirmed the fire is being treated as arson.
Enquiries into the car park blaze are also ongoing.
Anyone with information about either incident should call police on 101 or ring independent charity Crimestoppers on 0800 555 111.