Five men were shot when a gang forced their way into a house in east London.
Two of the gang initially tried to get into the property in Walthamstow but the residents fought them off with what are described as kitchen utensils.
Police said two more men then managed to get in and shot the five residents in the attack on Sunday.
The injured were taken to hospital by a neighbour where three were treated for minor injuries and two are said to be in a stable condition.
The four gunmen escaped in a Ford Ka and a Volkswagen hatchback with tinted windows.
Operation Trafalgar - which looks into non black-on-black gun crime in London - is investigating the incident.
Detectives are keeping an open mind regarding motive at this stage.
DS Neil Lemon said: "We are eager to trace the two vehicles involved in this incident, where it is believed that one of the men suffered from a head injury.
"The Metropolitan Police Service is dedicated to reducing gun crime and I appeal to anyone with information to contact us."