Four units of Dublin Fire Brigade are tackling a blaze in a derelict building in the inner city.
The fire broke out shortly before 8am close to St James's Hospital in the south inner city.
No injuries were reported, and it is believed the building was empty at the time.
James's Street was closed to inbound traffic, and gardaí are directing motorists. Service on the Luas Red Line was disrupted between Heuston and Blackhorse Stations.