The Donegal Fire Service attended a blaze in a residential area of Oldtown Letterkenny this Thursday morning.
The fire, which has now been extinguished, broke out behind the XL convenience store after approx 8am.
Nearby homes were evacuated due to the fire being in close proximity to an oil tank.
The junction at Oldtown and Rahan Road was closed for a period as emergency services dealt with the incident.
The road has since reopened, while the scene remains sealed off as Gardaí continue investigations.
There are no reports of any injuries.