Carlos Tevez has put his Manchester United future in doubt after he warned he will leave if his ongoing contract negotiations are not sorted out soon.

The striker, who was given time off over Christmas and the New Year to travel home to Argentina, is bound to feel the wrath of Sir Alex Ferguson after criticising his manager over reports suggesting he had rejected a new contract.

The 24-year-old's current loan deal ends after this season and he has been linked with a move to Real Madrid.

"I want to stay, but the club have not made any offer. I've been waiting for a year and a half," he told Radio del Plata in Buenos Aires. "If a club comes to me and offers me a five-year deal, I will accept it.

"I didn't like him [Ferguson] saying I didn't like the offer I was made because neither my agent nor me were given one. I don't know anything on my future. United know what they must pay if they want me to stay.

"I want everybody to know no offer has been made. I don't like that they are playing with our fans, who show their love to me in each match.

"I will sign my last contract and then I'll go back to Boca Juniors. That could be in four or five years."

Tevez (left) scored three times in the last round of the Carling Cup against Blackburn Rovers and had been expected to lead the line against Derby in tomorrow night's semi-final first leg at Pride Park.

But Ferguson will not be pleased by this outburst even though the Argentine insists he only wants what he feels he is owed.

Tevez has been at United for 18 months on a loan deal after leaving West Ham.

Old Trafford bosses have always said he would get a permanent contract and that his £32million purchase would be finalised. Tevez added: "I have not been making all sorts of demands. How could I? We have never had any talks."

New Real Madrid boss Juande Ramos is keen on Tevez and the player says he would love to face fellow countryman Lionel Messi who plays for Barcelona.

He said: "Who wouldn't want to play for Real Madrid?

"Like Manchester, they are one of the best clubs in the world and it would be a pleasure to play for them."

United have already paid between £6m and £10m to loan Tevez for the last two seasons.