A man has been arrested after a woman and two children were found with knife wounds in Norwich.
Police were called to an address in Mill Close, off Southwell Road, at about 1230 BST.
The woman, 23, and a three-year-old girl are in a critical but stable condition. A girl, six, is stable. All three are at the Norfolk and Norwich University Hospital.
A 28-year-old man was arrested in Great Yarmouth and is awaiting questioning.
Det Ch Insp Rickie Botwright, of Norfolk Police's vulnerable people unit, said: "This appears to be an isolated incident involving people known to one another.
"We are currently trying to establish the exact details surrounding this incident. At this time our investigations are ongoing."