An unidentified person has been arrested following the incident which involved two young children in the Ardoyne area in the north of Belfast.
One person has been arrested after a murder probe was launched following the death of a young child, with another left injured.
Police launched a murder investigation after an infant, reported to be two months old, was killed in Belfast on Tuesday night.
An unidentified person has since been arrested following the incident which involved two young children in the Ardoyne area in the north of the city.
Ambulance crews had earlier taken the two children to hospital following what is understood to have been a domestic stabbing incident in Brompton Park.
Police later confirmed that a child had died.
It is understood the other child, said to be aged two, is being treated for injuries in hospital.
A murder probe has been launched
“Police have commenced a murder investigation following the death of a child in the Brompton Park area of north Belfast this evening and made one arrest in relation to this,” said a Police Service of Northern Ireland spokesman.
“The investigation is at an early stage and further information will be provided in due course.”
North Belfast MP John Finucane tweeted: “Police have now confirmed a murder investigation into tonight’s tragic incident in Ardoyne with one person arrested.
“Our thoughts are with all those involved.”
SDLP deputy leader and North Belfast MLA Nichola Mallon said the local community was in shock.
“It is important that the PSNI are given the space and full co-operation to fully investigate this terrible incident,” she said.
The Northern Ireland Ambulance Service received a 999 call at 8.16pm on Tuesday.
A rapid response paramedic and two emergency crews attended.
A spokesperson for the ambulance service said: “The Northern Ireland Ambulance Service received a 999 call at 20:16 on Tuesday 27 July following reports of an incident in the Ardoyne area of North Belfast.
“NIAS despatched a Rapid Response Paramedic and two emergency crews to the scene. Following assessment and initial treatment two patients were taken to hospital in Belfast.”