A woman suspected of abducting her two young sons poses "a risk of harm" to the boys, a family court has said.
Samantha Baldwin was last seen on Monday near Nottingham city centre.
She is believed to be with six-year-old Dylan Madge and Louis Madge, aged nine.
Police issued a missing person appeal on Tuesday, and a day later said they are treating the disappearance as an abduction.
On Monday, Nottingham Family Court ordered the two boys be removed from the care of their mother.
In a highly unusual move, the court has now issued a statement in which it 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."
Nottinghamshire Police have said Ms Baldwin could be "harboured by someone", may have used a different name or changed her or the boys' appearance.
They have urged bed and breakfast operators and hotel and guest house owners and staff to check their registers.
Superintendent Rich Fretwell said police were "increasingly concerned" for the boys' welfare and safety.
"Samantha has no legal custody of the boys at this time," he said.
"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."
Two women, aged 62 and 36, have been released on bail after their arrest on suspicion of assisting an offender.
Ms Baldwin is described as 5ft 7in, of slim build, with shoulder-length blonde hair and green-blue eyes; Louis has collar-length straight fair hair, a fair complexion and blue eyes, while his brother Dylan has collar-length straight 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.