It followed revelations on insidethegames earlier this week that the bid had been hit by a new double racism row.

 

England is currently refusing to play an international friendly against European champions Spain in Madrid in 2009 because its players were racially abused during a match at Madrid's Bernabeu Stadium in 2004.

 

European football governing body UEFA, meanwhile, have ordered Atletico Madrid to play its next two Champions League home games, including the match next week against Liverpool, at a neutral venue because of violent and racist behaviour by the club's fans during a match against Marseille earlier this month.

 

Atletico has denied all claims of racism, insisting that UEFA officials confused chants of "Kun, Kun, Kun" - in support of the club's striker Sergio Aguero, whose nickname is "Kun" - with monkey cries.

 

But Mercedes Coghen, the chief executive of 2016, admitted that it is a major concern and could undermine the Spanish capital's chances of beating rivals Chicago, Rio de Janeiro and Tokyo to follow London and host the Olympics.

 

She said: "The bid is preoccupied about something that can affect us.

 

"We're working on it, but we ask the world of [Spanish] football, its president [Angel Villar] - who carries a lot of weight - and its players to react, to work for Spain because what affects us affects everybody."

 

It is the second high-profile incident to worry the bid in recent months after the men's basketball team posed for a publicity photo where they used their fingers to apparently make their eyes look more Chinese.

 

That image emerged during the Beijing Games, and the photo continued to be used for publicity purposes in Spain long past the Olympics.