The father of Madeleine McCann has described the sighting of a man seen on the night of her disappearance as being "significant" to his daughter's case.
Gerry McCann said he and his wife Kate welcomed the release of the information by the Portuguese police.
He said the sighting of a man "with what appeared to be a child in his arms" was both "significant and relevant to Madeleine's abduction".
The man is said to be white, 5ft 7ins, medium build with short hair.
He was seen on the night Madeleine was taken from the Praia da Luz apartment in the Algarve, Portugal.
Portuguese police went public with the description of the man seen on the night after pressure from the McCann family to move the investigation on.
But the family later said that police had got a crucial fact wrong in the description of the man.
The height of the man given on the Portuguese press release was 170cm (5ft 7ins) but it mistakenly appeared as 5ft 10ins in the English version.
Spokesman for the McCanns, Clarence Mitchell, said the family were happy that a description had been released but hoped every detail "would be absolutely accurate in every respect".
Wearing a dark jacket, beige trousers and dark shoes
Carrying "a child or an object that could have been taken as a child"
In a statement made to the press, Mr McCann said he and his wife welcomed the release of the "important" information which had come following an amicable and very constructive meeting with Portuguese police.
"We feel sure that this sighting of a man with what appeared to be a child in his arms, is both significant and relevant to Madeleine's abduction," he said.
The couple also appealed for more information about the man spotted by witnesses.
"Was this man seen anywhere else in or near the town with a child, or what appeared to be a child? What direction was he headed in? Did he have a vehicle?"
BBC correspondent Steve Kingstone in the Algarve said it was the first time the police had given a detailed description of a man they wanted to speak to.
But it is not known how long detectives had known this information or whether they believed the man abducted Madeleine, he added.
The BBC's correspondent said police were publicly playing down the similarities between the man described and the only official suspect in the case, Robert Murat.
Mr Murat denies any involvement in Madeleine's disappearance.
A family spokesman has also revealed Chancellor Gordon Brown has had several telephone conversations with Mr McCann.
Mr Brown offered both parents "his full support" in their efforts to find the four-year-old, who vanished on the night of 3 May.
Gordon Brown offered to support the search for Madeleine
The spokesman said: "Brown offered both Gerry and Kate his full support in their efforts to find Madeleine, although details of the conversations will remain private."
The Prince of Wales and Duchess of Cornwall also said on Saturday they had been following the case "closely and with deep concern" and "fervently hoped" Madeleine would be reunited with her family.
Madeleine, from Rothley, Leicestershire, was abducted from her bed in the Algarve resort as her parents ate dinner at a nearby tapas restaurant.