London (CNN) -- A new TV appeal for information about the disappearance of 3-year-old Madeleine McCann in 2007 has prompted almost 1,000 responses, London's Metropolitan Police said Tuesday.
The appeal is based on a new investigation and was aired on the BBC's "Crimewatch" program on Monday.
For six years, mystery has surrounded Madeleine's disappearance from her family's holiday villa in the resort town of Praia da Luz, in Portugal.
Now a review of the evidence by a team from London's Metropolitan Police appears to have raised the prospect of fresh leads.
The police have received more than 730 calls and and 212 e-mails since the appeal was broadcast, the case's lead investigator, Detective Chief Inspector Andy Redwood, said Tuesday.
"Detectives are now trawling through and prioritizing that material. This will take time," he said in a news release.
Callers give name for man in sketch
Police said Monday that two separate people had come up with the same name in response to computer-generated sketches of a man whom they are working to identify in connection with Madeleine's disappearance.
The man is described as white, between 20 and 40 years old, with short brown hair and a medium build. He was seen carrying a blond child, who might have been in pajamas and who was estimated to be 3 to 4 years old, around the time Madeleine disappeared, police said.
The two sketches, which police believe to be of the same man, are based on descriptions from separate witnesses, investigators said.
The same police appeal is to be screened in Holland on Tuesday and Germany on Wednesday in the hope of flushing out new information. The Portuguese resort is popular with people of many different nationalities.
The latest revelation is critical in reconstructing what exactly happened on the night of May 3, 2007, when Madeleine disappeared from her family's villa while her parents dined at a nearby restaurant. The girl was just days shy of her fourth birthday.
Neither her parents nor the detectives investigating her case have given up on one day finding the little girl from Leicestershire, England.
"There may be an entirely innocent explanation of this man, but we need to establish who he is to assist with our inquiries," Redwood said earlier.
Additionally, investigators believe they have a better understanding of when Madeleine may have been abducted, Redwood added.
"The timeline we have now established has given new significance to sightings and movements of people in and around Praia da Luz at the time of Madeleine's disappearance."
More sketches released
As police sift through the evidence, they have also released sketches of a fair-haired man or men seen near the scene on or around May 3, 2007, whom they would like to trace.
The detectives are investigating a spike in break-ins in the area in the weeks before Madeleine disappeared, two of them in the same block where her family was staying.
Police also said Monday they are looking into four separate sightings of charity collectors on May 3 in Praia da Luz. Two additional sketches were released of men described as Portuguese or Portuguese-looking.
The Metropolitan Police Service is offering a reward of up to £20,000 ($32,000) for information leading to the identification, arrest and prosecution of whomever is responsible for Madeleine's abduction.
Meanwhile, her parents continue to hold on to hope that their daughter will be returned to them, explaining on their website: "We still worry about her, we miss her as much as we ever did, we remain as determined as ever to find her and to know what has happened."
CNN's Sarah Aarthun, Erin McLaughlin and Stephanie Halasz contributed to this report.