Two people have been taken to hospital following a suspected gas explosion at a house in Hafod Road, Tycroes.
A witness described the explosion as “like a torpedo going off.”
The roof on the property has collapsed and emergency services are dealing with the situation.
A spokesman for Wales and West Utilities has said: "We have been alerted to an incident in Tycroes, Ammanford and we have dispatched an engineer to the scene.
"Their investigations are currently ongoing."