Neighbours are joining police to spend a second night searching for missing three-year-old Mikaeel Kular.
There is now grave concern for the young boy last seen when he was put to bed on Wednesday evening, with police saying they are exploring the possibility he may be the subject of "a criminal act".
More than 200 volunteers joined the hunt in Edinburgh but there have been no confirmed sightings.
Officers investigating his disappearance believe he could have left his Ferry Gait Crescent home of his own accord.
Assistant Chief Constable Malcolm Graham of Police Scotland said: "It is of grave concern that Mikaeel has been missing for nearly 48 hours.
"Since he was last seen on Wednesday night by his mum, and all of the work we've been doing, we've been unable to confirm any sightings of Mikaeel.
"As a result, our operations and our investigations are continuing in tandem but we must make sure we examine fully every possibility as to what might have happened."
Mikaeel, who has four siblings, was put to bed at 9pm on Wednesday and was reported missing the next morning by his mother, named locally as Rosdeep Kular, 33.
His jacket and shoes were missing and it is believed he may also be wearing black gloves with multi-coloured fingers, dark navy blue jogging bottoms, a grey pyjama top with an embroidered turquoise dinosaur on the chest and brown Clarks shoes.
It emerged yesterday that the youngster had not attended nursery since the Christmas break because he had been ill.
Police have not yet been able to confirm a potential sighting in West Pilton Gardens, around a mile from the family home, at about 8.30am.
Officers have thanked search volunteers from the local community for their " overwhelming support" in the hunt.
A Police Scotland spokesman said: "Further searches will continue on Saturday and any volunteers wishing to assist are asked to attend at the West Pilton Neighbourhood Centre in West Pilton Grove at 10am.
"Any members of the public coming along are reminded to dress for the conditions and ensure they have appropriate clothing and sturdy footwear.
"Officers will continue with this activity during the night."
Poor weather conditions are expected and police requested that only those aged over 18 assist in the search.
Anyone with information relating to the sighting or Mikaeel's disappearance is asked to contact the dedicated telephone number 0300 200 0200.