London: Portuguese police involved in the hunt for Madeleine McCann have joined the search for a Spanish girl who vanished in similar circumstances - leading to fears the cases may be linked.

Officers from the Algarve are looking for Mari Luz Cortes, 5, who disappeared from Huelva on Sunday.

The town is over the border in Spain, about 193km from Praia da Luz, where Madeleine, 3, vanished on May 3 last year.

It has emerged that Guilhermino Encarnacao, head of the Policia Judiciaria in the Algarve, is working on the case. He led the hunt for Madeleine but his team was accused of a series of errors, such as failing to preserve the crime scene, and they made her parents official suspects.

The new case will add to fears that a paedophile gang is active in the Iberian peninsula. Investigators from Spanish detective agency Metodo 3 - hired by the McCanns to find Madeleine - were in Huelva as a huge search continued.

A source close to the McCanns said Metodo 3 had interviewed Mari's parents: "They have sent representatives and are talking to relatives to establish what has happened and if there are any similarities [to Madeleine's case]. They are also talking to the Spanish police."

Mari vanished at about 5pm on Sunday after asking her mother Irene, 34, for money to buy crisps at a kiosk 100 yards from her home. On the McCanns' website, Madeleine's father Gerry said: "[Mother] Kate and I were dismayed to learn that a five-year-old girl has been missing... Huelva is approximately a two-hour drive from Praia da Luz. We went there in August to publicise Madeleine's disappearance.

"Hearing of the probable abduction of Mari has brought many awful emotions flooding back. We hope and pray Mari is returned safely to her family."

Metodo 3 believes Madeleine was kidnapped, driven to Huelva, an Atlantic port, and put on a boat to Morocco, where there have been alleged sightings.

Mari's father Juan Jose, a 34-year-old builder and former professional footballer, said: "It's possible the disappearance of my daughter is linked to Madeleine but it is not something we want to contemplate right now."

One hundred officers with sniffer dogs plus 500 locals are looking for Mari. Encarnacao said: "We were alerted through international protocols and we mobilised means of finding the child." One witness claims to have seen her on a bus, being shouted at by a woman.