Spanish police have arrested a French couple planning to "sacrifice" their five-year-old child who they believed was "possessed by the devil". 

Police sources said the couple, who were caught on a ferry crossing from Spain to Morocco, had "psychiatric problems" and the parents had a European arrest warrant for kidnapping a minor. 

The couple's 5-year-old child, whose arrest was ordered by the court, is in good health and is being held in a child care center before being extradited to France.