Istanbul, Madrid or Tokyo will host 2020 Games

The battle for the right to host the 2020 Summer Olympics entered the final stages on Tuesday with the Istanbul bid delegation saying its city would need to spend less than the other two finalists on "dedicated Olympic projects".

That claim will surprise many, as one of the Madrid delegation's strongest selling points was that the economic crisis in Spain would not affect its bid because its budget was a modest 2.37 billion euros ($3.12 billion) as most of the venues and the infrastructure are already in place.

The Istanbul bid, which is also up against the third candidate, Tokyo, may have hoped to take a bit of the wind out of the sails of Madrid, but the Spaniards had their own moment of triumph on Tuesday when they secured the support of four-time world footballer of the year Lionel Messi.

The 26-year-old Argentine's support for Madrid may have come as something of a rude shock not only to supporters of his club Barcelona - bitter rival of Real Madrid - but also to Istanbul, as he promotes Turkish Airlines, one of the main sponsors of the Olympic bid.

Istanbul, though, hopes the revelation that its budget would be the lowest in terms of expenditure will strike a chord with IOC members.

Several of the candidates seeking to replace retiring IOC president Jacques Rogge on Sept 10 have made it clear they don't want to see the Games getting bigger and unaffordable for some cities to host.

"Istanbul will have the lowest expenditure on dedicated Olympic projects," said Istanbul 2020's director of sport Alp Berker, just five days away from when International Olympic Committee members will vote on who hosts the Games.

"Three billion dollars worth are already completed and in the ground," said Berker.

Hasan Arat, the dynamic leader of Istanbul's bid, said the Marmaray rail tunnel - the deepest in the world - was a case in point of projects being completed.

"Our politicians promise and they deliver," he said.

"The Marmaray tunnel has fulfilled dreams that endured for 150 years of the Silk Road traversing East and West. Now there is a link between Beijing and London that brings great pride to all of our people."

Arat, a former professional basketball player, said Saturday's vote could be historic because an Istanbul win would bring the Games to a predominantly Muslim country for the first time.

"It would be a turning point for my country and also for the Olympic movement," he said.

That didn't sway Messi.

"I think it is good for sport if Madrid is awarded the Games - not only for the city, but also for the top-level athletes in Spain," said Messi.

"It is very important to host the Olympics in the country where I live.

"I was very lucky to participate in the Olympics for Argentina and it is an amazing experience for all athletes," said Messi, who arrived on Tuesday to prepare for a World Cup qualifier against Paraguay.

Tokyo, the only candidate city to have previously hosted the Games (1964), kept a lower profile with city governor Naoki Inose saying it remained firmly on track.

"Our bid is completely united, one 'Team Japan' with Prime Minister (Shinzo) Abe," said Inose.

"The overwhelming support from the Japanese people has given us even greater determination to do our very best to win," he said. "We are the safe pair of hands, one of the world's safest cities, and we have a substantial Games hosting fund of $4.5 billion already deposited in the bank."