Police are appealing for witnesses to an attempted aggravated burglary which left a Bermondsey family traumatised.
The incident occurred shortly after midnight on Saturday 9 June.
The family of six was watching television at their home in Grange Road, SE1, when three men burst through the open patio doors armed with a machine gun, a rifle and a machete.
The men threatened to shoot the family, including children and elderly family members. They demanded money and access to the safe but fled empty handed.
There were no reports of any injuries.
The first suspect is described as of Mediterranean appearance, possibly Turkish, aged in his thirties, 5ft 5inches tall, of slim build, wearing black clothing and a balaclava. He was armed with a large rifle, about two feet long.
The second suspect is described as of Mediterranean appearance, possibly Turkish, aged in his 30s, 5ft 7inches tall, of slim build, wearing black clothes and a balaclava. He was armed with a machete.
The third suspect is described as light skinned black male, of slim build, 5ft 9inches tall, wearing black clothes and a balaclava. He was armed with what was described as a machine gun.
DC Dave Reed from the Met's Flying Squad said: "These three men entered this family's home armed with an array of weapons, striking terror into the whole family.
"Two children were present at the time, and they have understandably been left traumatised by this incident.
"We are unaware of a motive and would ask the community for assistance. If you have any information about this incident, no matter how insignificant you think it may be, please contact police. You will be treated in the strictest confidence."
Anyone with any information is asked to contact the Flying Squad detectives on 020 8345 4219 or Crimestoppers on 0800 555 111.