Police have said it is "imperative" that anyone with information regarding the disappearance of four siblings six days ago comes forward to assist with inquiries.
Detectives are growing increasingly concerned for the welfare of the children, who haven't been seen since they were spotted leaving an address in Islington, north London, on September 16.
The siblings are believed to be with their father Zion Jackman and their grandmother Una Nolan.
The family have strong links to the West Midlands and Essex.
Detective Inspector Paul Ridley, from the North Area Public Protection Unit, who is leading the investigation, is now appealing for assistance from the public to help locate them.
Detective Inspector Ridley said: “It is absolutely crucial that we ensure the welfare of these young children. If you have seen them since their disappearance or know of their current whereabouts it is imperative that you come forward and tell my investigation team.
“My key priority is guaranteeing the safety of the children. Robust action will be taken if we become aware of any person intentionally assisting or facilitating their continued disappearance.
“I would encourage any person who wishes to come forward anonymously to do so. I can assure you that all information provided will be immediately followed up.”
Anyone who sees the children should call 999.
Anyone with other information on their whereabouts should call police on 101, or the Missing People charity on 116000, giving the reference number 21MIS027940.
Information can also be provided to Crimestoppers, anonymously, on 0800 555 111, or online at the Crimestoppers website.
