The warrants took place on Penyfan Road and Old Lodge Estate.
A spokesperson for Dyfed-Powys Police said: “Officers in Llanelli have today (April 13) carried out a targeting operation, seizing drugs believed to be heroin.
“The community saw an increased police presence around Llanelli as officers executed arrest warrants, undertook spot checks on identified individuals, properties and businesses and gave practical and emotional support to victims and witnesses of crime.
“The operation included search warrants – an important tool used to disrupt the supply of controlled drugs. Four people have been arrested on suspicion of possession with intention to supply class A drugs. The drugs, thought to be heroin with a street value of around £800, have been sent for testing.
“Llanelli Neighbourhood Policing Team was on-hand as a reassuring presence for the community and seeking feedback about how well the local policing team deal with crime.
“Dyfed-Powys Police worked with total focus on tackling the crimes that are impacting the most vulnerable people within communities. In addition, they offered tailored support for victims and witnesses of crime to help them through their experience.
“Anyone with concerns or information about crime and anti-social behaviour in Llanelli can report it to Dyfed-Powys Police by calling 101. If you are Deaf, hard of hearing or speech impaired text the non-emergency number: 07811 311 908.”
Old Lodge: Entry was forced into an address in Old Lodge, Llanelli. During the search a yellow kinder egg container was seized. The egg contained several snap bags of brown powder, believed to heroin. Two women, aged 54 and 34, were arrested for possession with intention to supply a class A drug, and remain in police custody.
Penyfan Road, Llanelli: Entry was gained into an address on Penyfan Road, Llanelli. Due to the rapid entry from officers, a quantity of brown powder, believed to be heroin, was saved from being flushed down the toilet. Further small amounts of brown powder were also recovered during the search. A man and woman, aged 32 and 31 respectively, were arrested for possession with intention to supply a class A drug, and remain in police custody.