Concerns are growing for two girls, who were reported missing at the weekend.
Angelica, 12, and 11-year-old Verity were last seen in the Newbold area of Rugby, in the early hours of Sunday, and police were "working round the clock" to try to find them, said Det Ch Supt Jon Belcher, of Warwickshire Police.
Officers are also carrying out house-to-house inquiries and making CCTV checks. Attempts to trace the girls, who are relatives, also include digital media searches.
"As the time has gone by since yesterday morning when they were last seen, our concerns have grown," Belcher said.
"There's numerous enquiries that have been taking place and I'm sure the residents of Rugby will have seen a lot of activity, including use of the police helicopter and lots of officers out doing house-to-house inquiries and CCTV checks."
At a press conference earlier, Belcher said he would not elaborate on any family relationships around the girls, other than to confirm they were related and believed to be together.
The girls had previously lived in Cornwall, he said, and the force was in contact with Devon and Cornwall Police as part of efforts to locate them.
As concern for them has grown, he said the force was now asking for the public's help in trying to find them.
'Refrain from speculation'
"So it's at this point in time where we really are now wanting to increase the vigilance of the public to look for these two girls and call us on 999 if they see them," he said.
"One of the messages I am keen to get out is that whilst we are grateful for the offers of people to come out and help search at this time, we have lots of specialist investigators and specialist search-trained officers who are out and about and untrained people coming into that may actually hinder us in trying to locate them," Belcher continued.
They may have changed clothes since going missing, he added.
He said police were getting more concerned as time went by, but he asked people to refrain from speculating around the case.
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