Two people have been arrested on suspicion of murdering a one-month-old baby girl, police said.
The 43-year-old man and 24-year-old woman are in custody.
Officers were called to a property in the Cwmbran area at around 10.35pm on Saturday by the ambulance service following concerns about the health of a baby.
The child was taken to the Royal Gwent Hospital, Newport, and then to the University Hospital of Wales in Cardiff. She was pronounced dead on Monday.
Gwent Police said that while the incident is being treated as suspicious, they are not looking for anyone else.