The emergency services were called to the property in Wogan Street at about 1630 BST following the blast.

Firefighters said the first and second floors of the house were badly damaged and it was structurally unsound.

No-one was injured in the explosion. The area around the house, which is close to the town clock and the castle, was cordoned off.

A fire caused by the explosion has been put out, but firefighters were unable to enter the property because it has been made unstable.

Fire crews from Whitland and Carmarthen were at the scene and were joined by an ambulance crew.