A search has been launched for a nine-year-old girl who has been missing overnight after she failed to return from school in West Yorkshire.
Shannon Matthews' disappearance was reported to police on Tuesday night after she did not return to her home on Moorside Road, Dewsbury Moor, Dewsbury.
Ch Supt Barry South said more than 200 officers were involved in the search.
He said officers were investigating the possibility that Shannon may have run away from home.
"We understand there may have been conversations with friends that she mentioned running away.
"If anyone knows where she is and or is aware of the fact that she has run away we would ask hem to get in touch with us as soon as possible."
Police said Shannon, who attends West Moor Junior School, has never been missing before.
She was last seen by teachers leaving the school at about 1510 GMT after she had returned from swimming.
Concerns were heightened after temperatures fell to -9C overnight.
Ch Supt South said the force's police training school had been shut down for the day to help the search.
"I have got over 200 officers supporting my local neighbourhood policing teams," he said.
"They have been speaking with friends, speaking with neighbours and relatives."
Officers are retracing the route which she may have taken on her way home.
Her uncle, Neil Hyett, 36, said dozens of local people had been out until 0400 GMT looking for the girl.
He said that Shannon, who lives with her mother, Karen, and stepfather, Craig, was a "timid" child.
Mr Hyett said: "We are extremely worried. Her brother, who is 11, has gone missing in the past but not Shannon.
"We've been out looking everywhere throughout the night but there's no sign of her.
"It was absolutely freezing. All the adults were so cold, so how cold would she be? We just need to find her, and find her quickly."
Shannon is described as white, 4ft 1ins (1.2m) tall, with shoulder-length medium brown coloured hair that was possibly tied up in a ponytail.
She is of slim build with blue eyes and freckles. She was wearing a black school jumper with a school logo on it, a white cotton T-shirt, black trousers and a black waist length coat with fur round the hood.
She wore pink and grey 'Bratz' furry boots.
A neighbour of Shannon's family, Peter Brown, said: "This is an extremely close-knit estate.
"Everyone knows everyone and we're just really worried.
"She's just a lovely girl and we just want to get her back."