Since then her parents, Kate and Gerry McCann, have spoken of the "anguish and despair" brought by their daughter's absence.
They discovered her disappearance on returning from a meal at a nearby tapas restaurant, having left their three children in the bedroom of their apartment while they ate.
Mr and Mrs McCann, both 38-year-old doctors, found the bedroom's windows forced open and the door ajar – although nothing had been taken from the room.
Portuguese police say they believe Madeleine has been abducted, but Mr McCann was unable to give any updates on the investigation in last night's statement.
He said: "We would like to thank everyone here in Portugal, the UK and elsewhere for all your support during this extremely difficult time for a family.
"We are pleased that the family liaison officers from Leicestershire are now working closely with the Portugese police officials and keeping us informed.
"We would again like to appeal for any information, however small, which would lead to the safe return of Madeleine."
Local police chief Guilhermino Encarnacao yesterday said detectives had a suspect in mind, but he was not able to discuss details out of fear of putting her life in danger.
It is thought that Madeleine and her abductor are still in the area she was staying in with her family when last seen.
Police in neighbouring Spain and regional airports and ports have been alerted to Madeleine's disappearance, while pictures of the three-year-old have been widely circulated.
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