International Olympic Committee (IOC) members were agonising yesterday over how to choose the host of the 2016 Games, with many said to be undecided just two days before the vote.

IOC members settling into their hotel in Copenhagen told The Associated Press that Tokyo, Madrid, Rio de Janeiro and Chicago are all capable of hosting the Games and there is no clear favourite.

Samih Moudallal, an IOC member since 1998, said tomorrow's vote, when cities will be eliminated in successive rounds of secret balloting, will be like choosing between 'four sons or your brothers'.

"How do you choose between your brothers?" Moudallal told the AP, adding that he has yet to make his choice. "You have to use your mind and your heart together. It's a very difficult choice."

And one that Michelle Obama wants to help them with. The United States first lady jetted into Copenhagen yesterday and was getting almost straight to work on meeting with IOC members before her husband, President Barack Obama, arrives tomorrow to give a final push to Chicago's bid.

Personal VIP appeals

With the contest so close, such personal VIP appeals could help sway the vote, although IOC members said they would likely not be decisive.

Spain's King Juan Carlos and Brazilian President Luiz Inacio Lula da Silva were also arriving as last-minute lobbying shifted to high gear. Japan's new Prime Minister, Yukio Hatoyama, is expected to arrive today.

As tension mounted, so did tempers. Despite fresh IOC warnings that the four candidate cities should avoid criticising their rivals, the Spanish Olympic Committee's Vice-President, Jose Maria Odriozola, told the national Efe news agency that "Rio is the worst bid".

Contrary to bookmakers' predictions, he said Madrid and Tokyo are the favourites.

Formal complaints

The Rio 2016 Olympics bid team formally complained to the IOC. In a statement to AP, Rio bid organi-sers said the comments were "totally unacceptable".

It said Rio was lodging a formal complaint to the IOC's ethics commission.

IOC votes can be highly unpredictable. Aside from the paramount questions of whether bidding cities' Olympic plans are technically and financially feasible, emotion, sentiment, geography, politics, self-interest and other factors also play a role.

IOC vice-president Chiharu Igaya said "many" IOC members are undecided and will choose only after the cities' final presentations tomorrow.

"The four cities are now neck-to-neck," he told the AP.