Superintendent Ian John, from Dyfed Powys Police, says search and rescue teams will continue to search through the night for April Jones.
In a statement updating the press, he said that helplines had received more than 2,500 calls from members of the public, which were being analysed by every police force in England and Wales.
Wearing a pink ribbon in support of a campaign by the five-year-old's family, Mr John said investigators remain "determined" to find April following her disappearance on Monday.
The Superintendent thanked volunteers who had answered questionnaires to aid the search, saying: "All in all, we've had outstanding co-operation from members of the public, not just from this community. It quite takes you away really, it's quite a humbling experience."
He added: "I want to turn to April's family. I'm sure we all are feeling for them at this terrible time, also the friends and the extended family.
"I just want to remind everybody that's why we're here tonight, in the pouring rain in Machynlleth, is to focus on the search and do everything that we can to bring this operation to a conclusion."