A woman suspected of abducting her two young sons poses "a risk of harm" to them, a family court has warned.
Samantha Baldwin, 42, vanished with Dylan Madge, six, and Louis Madge, nine, on Monday after a court ruled they should be removed from her care.
A missing persons appeal was launched on Tuesday and, on Wednesday, police announced the investigation had become an abduction inquiry.
A statement Nottingham Family Court, which had made the ruling, said: "It is assumed that she has abducted Louis and Dylan. The children have now been made wards of court.
“Miss Baldwin is considered to pose a risk of harm to the children."
On Friday, Nottinghamshire Police Superintendent Rich Fretwell said officers were growing "increasingly concerned" for the children's welfare and safety.
He said: "Samantha has no legal custody of the boys at this time.
"Our investigation team are exploring a number of lines of inquiry. There's always the possibility that Samantha could be being harboured by someone.
"We would urge that person to come forward and let us know where the boys are."
Police called on owners and staff at guest houses, bed and breakfasts, hotels and caravan parks to check their registers and be aware she may be using a different name.
Two women aged 62 and 36 who were arrested on suspicion of assisting an offender have been released on bail.
CCTV images from the same day as the hearing showed Ms Baldwin alone at two locations in Nottingham city centre.
She is described as 5ft 7in and of slim build with shoulder-length, highlighted blonde hair and green-blue eyes and was last seen wearing a red knee-length coat.
Louis has collar-length straight fair hair, a fair complexion and blue eyes, while Dylan has collar-length straight dark brown hair, a tanned complexion and brown eyes.
Anyone with information should call Nottinghamshire Police on 101 urgently, quoting incident number 332 of March 27.