Police investigating the disappearance of five-year-old April Jones, playing outside her home on Monday evening, have said there was "no sign of a struggle" at the scene.
Detective Superintendent Reg Bevan said April, who police believe was abducted last night from near her home in Machynlleth, mid Wales, got into the drivers' side of a grey van which may have been a Land Rover or Ford Connect-type vehicle.
Bevan, from Dyfed Powys Police, told a media conference that getting "vital" information from the children who witnessed what happened to April is a "delicate and time-consuming" task.
He said they could not say for sure whether April was led to the vehicle or went there herself, but added: "The indications are that she got into the vehicle willingly."
April Jones: She was wearing a purple coat when she disappeared
"I am mindful that we are still in the process of speaking to these children," he said.
"We are trying to extract exactly what they have seen and we are very anxious to provide the most accurate information we can without misleading anyone in any way."
Bevan said police were keeping an "open mind" in relation to the question of whether April had been taken by a stranger of someone she knew.
"We are keeping an open mind, we are pursuing all lines of inquiry," he said.
"Clearly April has got into the vehicle, there is nothing to suggest otherwise, so we are mindful of the circumstances that led up to that.
"I am unable to give too much information because it is early days in the inquiry and we are anxious that the information that I am able to give is something that we can confirm."
Bevan said the force would be combing through CCTV, both municipal and private, to find clues about the abduction of the five-year-old.
The abduction of a five-year-old girl last night is "every family's worst nightmare", Bevan said. "It is a very difficult time for them and we have specialist advisors with them."
Children's toys discarded in the estate near where April Jones lives, Machynlleth
He said specialist advisors from across the country were helping police with the investigations. Two helicopters have been deployed to search the area.
Charlie Hedges, manager for missing, abducted and kidnapped children at the Child Exploitation and Online Protection Centre (Ceop), said he was called at 11pm on Monday for help on the case.
"There are the challenges of how you interview a child to get the right information, and with the time of day. You can't interview them through the night."
Police have split the search parties into 10 groups of 20 people to search different areas, led by search-and-rescue experts.
The Daily Mail reported that April's parents are Coral, 40, and Paul, 43 are "beside themselves with worry."