United have always insisted Ronaldo, who is only one year into a five-year contract which runs until 2012, is not available at any price.
But he has long spoken of his desire to play in Spain and Real have repeatedly spoken of their interest in signing him.
On Thursday, the simmering dispute between the player and United took a new twist when Fifa president Sepp Blatter entered the debate, saying there is "too much modern slavery in football," a comment on transfer trends that Ronaldo then said he agreed with.
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