It is widely predicted that the race is now down to a contest between the American city and Rio de Janeiro but Rogge has claimed it is too close to call.

He said: "I see really no favourite.

"I think it's going to be a very close vote.

"I think the final vote will be decided by a couple of votes only."

Echoing what London 2012 chairman Sebastian Coe said earlier this week, Rogge said he expects the result to be as close or closer than the vote in Singapore in 2005, when the British capital defeated Paris by four votes in the final round to win the right to stage the Games.

Rogge said: "There is no bid that is lagging behind.

"All the scenarios are possible."

One of the big uncertainties is whether Obama will travel to Copenhagen for the IOC Session, where the final vote will take on place on October 2, to lobby members for Chicago's campaign to bring the Summer Olympics back to the US for the first time since the 1996 Atlanta Games.

Brazilian President Luiz Inacio Lula da Silva has said he will be there to try to persuade the IOC to send the Olympics to South America for the first time.

King Juan Carlos of Spain will be there for Madrid's bid.

Japan has invited incoming Prime Minister Yukio Hatoyama and Crown Prince Naruhito to attend.

Rogge said he has no information about Obama's plans and had firm confirmation only of the Spanish King's attendance.

He said: "I expect this to come out probably in a fortnight at latest because there are security arrangements, there are protocol issues, there is accommodation.

"I guess all of this will crystalise in the next two weeks."

Rogge dismissed speculation that Chicago's chances will be harmed if Obama (pictured) fails to travel to the Danish capital.

He said: "Absolutely not.

"There is no obligation to come.

"There is neither a tradition for all the heads of state to come.

"We wouldn't see that as being negative whatsoever.

"I'm sure that if a head of state will not be coming, that head of state will definitely make a video presentation or send letters and things like that."

Rogge said he would make no judgment on whether Obama or the other leaders should be in Copenhagen.

He said: "If they want to come, this is an honor for the IOC.

"We'll feel honoured by their presence.

"It would be absolutely legitimate if they go to defend the bid of their country.

"We are not asking for heads of state to come there.

"They are most welcome, but this is not something that we consider as being the most important thing.

"It is symbolically important.

"They have an influence by their charisma, but it is not something the IOC is seeking and going after.

"I think what counts most is the confidence that the members have in the future organisers.

"It's an issue of a human chemistry.

"The question we're going to ask ourselves is: A, is the file a solid one?

"And B, do we trust the people who made the bid to be the ones who will deliver?

"Do we trust these people?....I think everything being equal between the four candidates, it's the human factor that will be the most important."


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