Police say the device was found during the execution of a planned search warrant, under The Explosive Substances Act, at the address.
The area around the property was cordoned off on Wednesday evening (11 June) while specialist explosive ordinance disposal (EOD) officers made the device safe.
Residents within the cordon were evacuated to the nearby Leisure Centre.
(Image: Hidden Carmarthenshire)
Dyfed Powys Police issued an update at 9.50pm to say that EOD officers had concluded their searches. One device was made safe, and they no longer believe there is any wider threat to the public.
Residents who were asked to leave their properties were then able to return with all roads within the cordon reopening.
Officers remained at the location overnight while enquiries continued.
Police say a 57-year old man remains in police custody on suspicion of offences under The Explosive Substances Act.
Chief Inspector, Dominic Jones, from Dyfed Powys Police said: “I would like to thank the whole community for their support and patience while we dealt with this incident. Local people will see more police in the area over the coming days as enquiries continue.”
