British police investigating the disappearance of toddler Madeleine McCann are in the Algarve, where they are meeting with Portuguese counterparts over the possible arrest of three suspects, British media have reported.
Four Scotland Yard detectives arrived on Tuesday for talks about the three-year-old's 2007 disappearance from a holiday apartment in the southern Algarve resort of Praia da Luz, according to the Daily Mirror.
Metropolitan Police would not confirm the report.
Portuguese authorities closed their investigation into her disappearance in 2008, but Scotland Yard spent two years reviewing it at the British government's request and opened their own probe in July last year.
Madeleine McCann went missing in May 2007 while her parents were dining with friends at a nearby restaurant, leading to a global search that gripped the world's media.
The police have since found mobile phone records which showed the three men in question made numerous calls to each other in the hours after the three-year-old disappeared, the mass-selling newspaper said.
Britain's prosecution service has sent an International Letter of Request to Portuguese police seeking permission to arrest the trio, the paper added.
A spokesman for the police confirmed that a letter had been sent to the Portuguese authorities, but declined to comment on the contents of the letter.
"We can confirm a second International Letter of Request has been sent to the Portuguese authorities," the spokesman said.
Despite huge international interest and numerous reported sightings from Belgium and Spain to Morocco, France and Malta, and investigations stretching as far away as Australia, the girl's fate remains a mystery.
Her parents were named as official suspects by Portuguese police four months after Madeleine's disappearance, but in 2008 they were cleared and Portugal's public prosecutor later dropped the case, citing a lack of evidence.
London police launched a review of the case in 2011 and began their own investigation in July last year.
The McCanns have led a six-year campaign to find Madeleine, who they believe was kidnapped and is still alive.
An unnamed source told the paper that the couple were "on tenterhooks" as they wait for further developments.
The suspects are believed to be part of a burglary gang.