Portuguese police were last night investigating claims that missing four-year-old Madeleine McCann's body lies buried in scrubland only nine miles from where she was abducted.

An anonymous letter and map, sent to Dutch paper De Telegraaf, identifies an area under rocks north-east of Praia da Luz, from where Madeleine vanished on May 3.

Last night police officers spent an hour and 20 minutes examining fields and the surrounding area around the village of Arao ahead of possible searches starting in the morning.

Parents Gerry McCann, a Glasgow-born cardiologist, and his wife, Kate, were said to be on tenterhooks after hearing the message strongly resembles a letter sent to the same newspaper last year, accurately pinpointing where two missing Belgian girls were buried.

A source close to the family said they were with Portuguese police when news of the letter came through. It was only when it was translated that they realised its contents.

"They found the whole thing very upsetting," he said. "It is being taken as seriously as any other line of inquiry."

Chief Inspector Olegario Sousa said "everything necessary" was being done to validate the allegation.

De Telegraaf said that the letter claims Madeleine is buried "north of the road under branches and rocks, around six to seven metres off the road" in a barren and deserted landscape.

Beside a cross and two question marks, the sender has written "vermoedelijke vindplaats Madeleine" - the place where Madeleine can probably be found.

Police have not started a detailed search of the ground amid concerns that the co-ordinates are not detailed enough.

"There have been exchanges between Dutch police and us," said Mr Sousa. "The information indicated an area 15km from the place of her disappearance."

Asked if any search would involve digging, he said: "If the information gives us a precise location, we will do it."

Dutch police spokesman Rob Van der Veen said the letter had "grabbed our attention" coming in the wake of the tip about the Belgian disappearance.

Police are examining the similarities between the new letter and the one pointing to the whereabouts of step-sisters Stacey Lemmens, seven, and Nathalie Mahy, 10.

A convicted paedophile, Abdullah Ait Oud who is of Moroccan descent, is being held in custody awaiting trial for the murder of the girls. He has always denied the charge.

The Telegraaf believes the letter comes from the same sender because handwriting was similar and the phrase "vermoedelijke vindplaats" was also used in the tip-off letter last year.

The map, thought to have been taken from Dutch route planning website routenet.nl, identified a dirt track road north of Odiaxere.

The McCanns lived in Amsterdam for a year in 2004 when Madeleine was a baby and Mrs McCann, 38, was pregnant with twins Sean and Amelie.