Police have arrested a teenage boy in connection with the incident. He is being questioned on suspicion of murder and attempted murder.
A woman is also understood to have sustained injuries during the incident.
Emergency services were called to a property on Lisnahull Road shortly after 11am. Despite efforts at the scene, the man was pronounced dead at the property.
It is understood that a neighbour raised the alarm after hearing a woman inside the house calling out for help.
The young girl was taken for medical treatment following the incident and is understood to be seriously injured.
A large section of the area surrounding the property has been sealed off while forensic investigators examine the scene. Police are expected to carry out further inquiries as they work to establish the circumstances surrounding the attack.
The incident has left the local community deeply shaken, with residents coming to terms with the loss of life and the serious injuries suffered by others.
Local Sinn Féin councillor Deirdre Varsani said the community was experiencing a strong sense of shock following the incident.
She said the immediate priority was to support the victims, those who may have witnessed what happened and others affected by the incident.
Councillor Varsani also warned that the emotional impact could continue to be felt throughout the area in the coming days and weeks.
