United report Real to FIFA

United warned Real two weeks ago that they would take drastic action if the Spanish champions continued to unsettle their most prized asset.

Since then, the double-winners do not consider Real to have made any effort to end the speculation, forcing them to make an official protest to FIFA.

A statement on the club's official website read: "On 27 May, Manchester United made clear its intention to report Real Madrid to FIFA if it continued to involve itself in the future of Cristiano Ronaldo.

"Unfortunately, Real Madrid has not kept its own counsel and the club feels it has no alternative but to make a formal complaint to the world governing body, which it has done today [Monday].

"The precise content and nature will remain confidential."

FIFA spokesman Pekka Odriozola said: "It is too early to say how the matter will be dealt with.

"We will first have to look at the precise nature of the complaint before seeing what steps will be taken."

Real have made no secret of their admiration for Ronaldo and the player himself has repeatedly refused to pledge his future to United or rule out a move to the Bernabeu.

The 23-year-old, who scored 42-goals for United last season on their way to the Premier League title and Champions League glory, has said he will clear up the speculation over his future once his involvement in the European Championship with Portugal comes to an end.