August 15 - Fresh doubts have been raised over Rio de Janeiro's ability to be ready to host the 2016 Olympics and Paralympics following the resignation of Marcio Fortes, head of the Olympic Public Authority (APO).

The APO said Fortes told Brazil President Dilma Rousseff he was resigning after complaining to her his office had lost its influence.

The APO coordinates preparations for the Games between Brazil's Federal, State and Local Governments and under Fortes, a Government Minister in the Cabinet of former President Luiz Inacio Lula da Silva, was responsible for coordinating a variety of tasks related to hosting the Games.

Brazil has committed $11.6 billion (£7.4 billion/€8.8 billion) toward infrastructure including security, telecommunications and energy projects.

It is also spending more than $13 billion (£8.5 billion/€10 billion) on next year's FIFA World Cup.

Brazil's Sports Ministry said in a statement that it "has always maintained good relations, appreciation and respect for Marcio Fortes."

A replacement will be chosen by the President's office, which confirmed Fortes's resignation.

The resignation will be high on the agenda when the International Olympic Committee (IOC) Coordination Commission, chaired by Morocco's Nawal El Moutawakel, arrives for its next inspection of Rio's preparations at the end of this month.

The IOC has previously expressed concerns that planning and construction are moving slowly.

Earlier this month, Leo Gryner, chief operating officer of Rio 2016, admitted $700 million (£450 million/€500 million) in public money may be needed to cover a shortfall in the operating budget.

The operating budget - to run the Games - was listed at $2.8 billion (£1.8 billion/€2.1 billion) in the original bid document.

Gryner acknowledged in an interview with The Associated Press, that the budget is likely to reach up to $4 billion (£2.5 billion/€3 billion).

The cost of the Olympics and the 2014 World Cup has already been the subject of public protests with from demonstrators upset at Brazil's poor schools and health care system.