With roughly only 24 months to go, the International Olympic Committee is wondering if Rio de Janeiro will ever be able to complete its preparations in time for the 2016 Olympic Games. An IOC senior official has blasted the country's preparations for the global games as the worst ever that he has seen so far.

The civil unrest and governmental chaos in Brazil had spilled over preparations for the games, rendering construction delays of sporting venues. Soaring costs and how it should be shouldered among the municipal, state and federal governments are also dampening factors.

"The situation is critical on the ground," John Oates, an IOC vice president from Australia, said "We have become very concerned. They are not ready in many, many ways. We have to make it happen and that is the IOC's approach. You can't walk away from this."

The concern might really be so huge that the IOC sent a number of its executives to oversee how preparations are being made at the South American country.

But Eduardo Paes, Rio mayor, said some of the delays were caused by the IOC's huge demands.

"Probably these federations will keep complaining about me until the day the Olympics start, because sometimes they want us to do things that are too large," Mr Paes said. "They are making demands about the stadiums, but I will not accept them."

He cited the 20,000-seat tennis facility the IOC wanted built for the Olympics. Mr Paes found it impractical and thus downsized it to 10,000.

"We are not going to deliver glamorous stadiums that will become 'white elephants' in the future, like Beijing did with the 'Birds' Nest,'" Mr Paes said. The Birds' Nest is the 90,000-seat Chinese monstrosity now unused except for spiders' cobwebs.

"My focus is on the legacy for my city," Mr Paes said. "The demands are about the stadiums."

When Rio de Janeiro submitted its bid, it said it would spend about $15 billion for the 2016 Olympic Games.

"The IOC has adopted a more 'hands-on' role," Mr Coates said. "It is unprecedented for the IOC but there is no Plan B. We are going to Rio."

As expected, the local organising committee for the 2016 Rio de Janeiro Olympics vowed to speed up.

"The time has now passed when general discussions about the progress of preparations contribute to the journey towards the Games," the organising committee said in a statement. "It is time for us to focus on the work to be done and on engaging with society."

"We have a historic mission: to organize the first Olympic and Paralympic Games in Brazil and in South America. We are going to achieve this," the LOC said.

"In 2016, Rio will host excellent Games that will be delivered absolutely within the agreed timelines and budgets," it added.