A 24-year-old Hempstead man was killed after at least one gunman opened fire outside a children?s birthday party on Jackson Avenue early Saturday morning, police say.

According to investigators, the shooting happened shortly after midnight in the second-floor hallway of an apartment building, where children were playing at the time of the incident.

When shots rang out, police say a 9-year-old girl and another man were also hit in the arm. They were treated at a nearby hospital and are expected to recover. The woman who hosted the party says her 8-year-old son pulled the wounded girl back into the apartment, and then they barred the door.

People who attended the birthday party say they have no idea what motivated the gunman to open fire.