LONDON (Reuters) - The seven-year search for missing British girl Madeleine McCann, who vanished on a family holiday in Portugal, is heading towards "a substantial stage of activity" although this did not mean a breakthrough was in sight, British police said on Thursday.
McCann was three when she disappeared from her room at the Praia da Luz holiday resort in the Algarve in May 2007 while her parents were dining with friends at a nearby restaurant, prompting a global hunt and worldwide headlines.
Despite the international attention, the fate of McCann, whose case remains extremely high-profile in Britain and attracted the involvement of Prime Minister David Cameron, remains a mystery.
"In forthcoming weeks we are going to be going to a substantial stage of operational activity on the ground in Portugal," London Police Assistant Commissioner Mark Rowley
told reporters. He added: "I want to keep expectations down. You shouldn't read into this that this is necessarily an end game or about to be a breakthrough of anything like that."
London police began a review of the case in 2011 at the instigation of Cameron following appeals from McCann's parents, and then launched their own investigation in July.
The new inquiry has thrown up a number of leads and last month, British police said their officers and colleagues in Portugal were investigating a string of sexual assaults or attempted abductions involving British children between 2004 and 2010.
In March, the British team also said they were in contact with their counterparts in Spain, Belgium, Switzerland, Netherlands, Germany and the Channel island of Jersey.
The upcoming activity is likely to involve searches, speaking to suspects and people of interest, and checking telephone dates and financial records.
"When you've got a massive investigation like this where you've got multiple lines of inquiry, potentially different hypotheses as to exactly what happened, then you have to systematically work through them all," Rowley said.
"If we didn't think there were any potential fruitful lines of inquiry we wouldn't be where we are today."
The main thrust of Rowley's briefing was to appeal to the media not to interfere with the inquiry or report planned operational activities before they had been carried out.
Police say the McCann hunt had probably attracted more media attention in Britain than any previous case. There was frenzied reporting by British tabloids in the aftermath of her disappearance, each desperate to cover any potential lead ahead of its rivals.
On their last trip to Portugal, Rowley said detectives were mobbed by reporters looking for updates.
McCann's parents, Gerry and Kate, their friends who were with the couple on the night she vanished and a British man who lived nearby have all won hundreds of thousands of pounds in damages following libel action against newspapers.
"There's a tendency sometimes on this case, because it has such interest for hyperbole, in some of the reporting," Rowley said. "It's unhelpful if everything we do is reported as a breakthrough. I know we all want the same outcome in trying to get to the bottom of this."
Editing by Mark Heinrich