A "potential sighting" of a child matching the description of missing three-year-old Mikaeel Kular is being investigated by police.
Members of the public reported seeing a boy who was "small in build and alone" in West Pilton Gardens, Edinburgh, at around 8.30am yesterday morning.
The timing of the sighting has been confirmed by CCTV but it cannot confirm the identity of the child, Police Scotland said.
Mikaeel disappeared from his home in the Scottish capital after being put to bed on Wednesday night.
Hundreds of people have joined in the search for the missing youngster as police said they are becoming increasingly concerned.
Officers are now asking for the public's help in light of the possible sighting.
Police want anyone else who saw the child to get in touch urgently as they work to confirm whether it was Mikaeel or another youngster.
They said the small boy matched the description of Mikaeel, although the child was also wearing a cap or hat.
Superintendent Liz McAinsh said: "Since Mikaeel was reported missing, we have been contacted by a number of people with information which we have been working to assess and respond to.
"Members of the public have come forward to report seeing a boy walking in the vicinity of West Pilton Gardens at 8.30am yesterday.
"The witnesses were in a vehicle driving down West Pilton Gardens at the time they saw the boy.
"They described seeing a small boy on the right-hand side pavement running towards the junction with West Pilton Park.
"They noticed him because he was small in build and alone at the time. They said he matched the description given of Mikaeel, although they also reported the child they saw was wearing a cap or hat."
She added: "We would ask that anyone who also saw this child contact us as a matter of urgency. We need to confirm if this was Mikaeel or if it was another child. If it is your child who was out at this time and in this location, we want to hear from you so we can eliminate this line of inquiry as swiftly as possible."
Anyone with information relating to this sighting is being asked to contact the dedicated telephone number 0300 200 0200.