An 11-year-old girl is fighting for life after being stabbed alongside her mother and two sisters.
Police were called to Livingstone Road in Enfield at 12.13pm on Saturday to reports of an injured woman.
A woman in her 30s and three girls aged under 12 were all found suffering from stab injuries.
Following intensive treatment at hospital the woman and two of the children are not in life-threatening conditions.
One girl aged 11 remains in a critical condition.
A 44-year-old man was arrested at the scene on suspicion of attempted murder and has been taken to a north London police station where he remains for questioning.
One neighbour, who asked not to be named, said: "I heard screaming and then I saw a woman lying down on the ground where the (police) tent is."
The 51-year-old man said he was listening to the radio when he heard a woman screaming.
"I turned the radio off, then heard the screams separating, like three or four times within a few seconds."
DS Joe Stewart from Enfield CID said: “This was an appalling attack on a woman and her young children. They have sustained very serious injuries. Our thoughts are with them as they continue to receive vital treatment in hospital.
“Attacks like this on such young people are extremely rare. At this early stage of the investigation, we are not looking for anyone else in relation to this incident. The attacker was known to the victims. There is no further risk to the public at this time.
“If you have information about this incident I would urge you to get in touch and speak with investigators.”
Livingstone Road remained closed on Saturday at the junction with the North Circular Road, the A406
Motorists are being advised to avoid the area.
Anyone with information is asked to call police on 101 quoting CAD3735/06July or Crimestoppers anonymously via 0800 555 111.
