An overnight search involving 40 officers, dog handlers and mountain rescue teams has failed to find April Jones, police have said.
The five-year-old was abducted from near her mid-Wales home at around 7pm on Monday and hundreds of people have joined the search for the missing youngster.
Superintendent Ian John of Dyfed Powys Police warned of the "challenging conditions" facing search and rescue teams and asked members of the public to leave today's search to "members of our trained and skilled teams".
A 46-year-old man, named locally as Mark Bridger, remains in police custody after being arrested yesterday on suspicion of abduction. He is known to April's mother Coral and father Paul.
On Tuesday night in a statement her family said they had been left "shattered" by the abduction.
Mr John said police and a mountain rescue team had carried out "systematic and methodical" searches around Machynlleth throughout the night. Police are now expecting intelligence arising from interviews with the man in custody to drive the search operation, he added.
Commenting on the enthusiastic help from volunteers in the search effort, he asked for the hunt to now be left to the police, saying: "I need people to know it is a rural environment, very challenging conditions out there. The weather yesterday wasn't great and I don't think the forecast is very good for today.
"The River Dyfi is in flood and we really do need to manage the risk of everybody there, not only the police officers, the mountain rescue team, but we are extremely concerned about large numbers of members of the public going into what I have said are very challenging conditions.
"So what I am asking really is, notwithstanding the great support and the commitment that people want to show in helping us to find April, can we please leave this now to the trained and skilled people that we have. I don't want those officers to be distracted by the well-intentioned and enthusiastic support," he added.
Mr John said experience suggested any breakthrough in the search for the missing five-year-old would be at a local level. April was last seen playing with friends on the Bryn-y-Gog estate close to where she lived in Machynlleth. Mr John said some of the key areas may be re-visited, adding: "It is likely that we are going to find somebody in the search parameter where she was last seen."