The parents of Madeleine McCann were yesterday said to be "extremely concerned" to learn that another child had gone missing 120 miles from where their daughter disappeared.

Five-year-old Mari Luz Cortes was last seen at a sweet stall at about 5pm on Sunday in the Spanish town of Huelva. Her parents believe she was abducted.

The port is 25 miles from the Portuguese border, only a two-hour drive from Praia da Luz in the Algarve where Madeleine was snatched on May 3 last year.

Kate and Gerry McCann, who is originally from Glasgow, made at least one trip to Huelva to highlight the case of their missing daughter, believing she may have been driven through the Andalucian town by her kidnapper.

There is no border control between Spain and Portugal at Huelva and the frontier was not closed off on the night Madeleine disappeared. Portuguese border police were not informed Madeleine was missing until the following morning.

Members of the country's Borders and Aliens Service were only given a photograph of the Spanish toddler 12 hours after she disappeared.

Detectives searching for Mari Luz are understood to be investigating one theory that she may have been taken as part of a "gypsy feud".

She is of gypsy origin and a travelling circus was said to have been in the area at the time.

A massive search of Huelva by police has failed to find any trace of her. Fears that she has been abducted were supported on Monday evening when a woman said she had seen a girl fitting Mari Luz's description on a local bus at 8pm on Sunday. The girl was with a gypsy woman who kept shouting at her to stop crying.

Mari Luz's mother said she believed the woman because the clothes she described the girl as wearing fitted her daughter's description.

It was reported in Spain yesterday that Juan Jose Lopez Garzon, the government delegate in Andalucia, has said "all possibilities" are being investigated in the disappearance of the five-year-old.

The TypicallySpanish.com website reported him as saying information on the case has been passed to Portuguese authorities and that a protocol of collaboration has been effected.

Yesterday the McCanns' spokesman, Clarence Mitchell, said that the family's investigators would be trying to establish whether there is any link between the disappearances of Madeleine and Mari Luz.

He said: "Kate and Gerry are now fully aware of the disappearance of Mari Luz Cortes and are extremely concerned to hear that another young girl has gone missing."

It was confirmed yesterday that Portuguese investigators are seeking to re-interview friends of the McCanns in Britain and are in contact with the UK authorities.

The friends - dubbed the "Tapas Seven" - were on holiday in Praia da Luz with the McCanns when Madeleine vanished.

Portuguese detectives are reported to be ready to fly to the UK to sit in on fresh questioning of them by British police.

Portugal is seeking the assistance of Eurojust - the European Union's judicial co- operation agency - in securing the help of British authorities.