One man has been taken to hospital after a fire in the stairwell of a block of flats at Granby Close in Llanelli.
Mid and West Wales Fire and Rescue Service have the fire under control.
Police said one man has been taken to hospital as a precaution with smoke inhalation, while four people were also treated at the scene.
Due to concerns for safety, four blocks of flats have been evacuated and a 100 metre cordon is in place.
Fire officers have now left the scene.