Copenhagen  - Rio de Janeiro was elected host city of the 2016 Olympics on Friday as the International Olympic Committee finally entrusted the unchartered territory of South America with the world's premier sports event.

IOC president Jacques Rogge announced that the Brazilian metropolis Rio won a final round of IOC voting against Madrid after first Barack Obama-backed Chicago and then Tokyo crashed in the earlier rounds of the secret ballot.

Rogge said that "the Games of the 31st Olympiad are awarded to the city of Rio de Janeiro" as the Brazilian camp led by the nation's president Luiz Inacio Lula da Silva erupted in a collective frenzy in the auditorium in the Bella Center in Copenhagen.

Football legend Pele and other delegation members cried tears of joy as Rio were later Friday to sign the official host city contract.

Rio won the final round by a mile, 66-32, after gaining control in the second round with 49 votes to Madrid's 29 and Tokyo's 20. In the first round, Madrid had 28 votes, Rio 26, Tokyo 22 and Chicago 18.

Olympians will enjoy competition in the famous Maracana stadium and the Copacabana beach as Rio took another huge step towards one of the leading nations in the world.

"This is great for the universality of the Games," said German IOC vice-president Thomas Bach.

The IOC had in the past snubbed South American bidders (among them Rio four times), seemingly considering South America not ready yet to stage the Olympics which bring together more than 10,000 athletes and tens of thousands of officials and media.

But the 2016 IOC evaluation commission already said in its report that Rio was capable of staging excellent Games which will come two years after the nation Brazil hosts the 2014 football World Cup.

An emotional presentation earlier Friday saying that it was South America's turn for the 31st edition of the Games did also seemingly impress the Olympians.

"Rio is ready, give us this chance and you will not regret it," said Lula.

"I honestly believe it's Rio's time... It would send a powerful message that the Olympics belong to all continents, all humanity."

Rio then pleaded more than sun and samba, a major legacy for the next generation in a country catching up rapidly with the top economic powers in the world.

"Brazil is ready, Rio is ready to host Games of certainty, celebration and transformation," said bid chief Carlos Arthur Nuzman.

Mayor Eduardo Paes said that hosting the 2014 World Cup was no disadvantage, but that it is rather "our aim to use the World Cup as a springboard to greatest possible Games in 2016."

Lula also dismissed IOC scepticism whether Rio could really deliver the Games set for August 5-21, 2016.

"Brazil has learnt to abide by its commitments. We need to prove every day to the world that Brazil has decided to transform itself into a developed nation," he said.

A huge infrastructure operation is necessary for the two big events, estimated at almost 14 billion dollars. The Olympic budget itself will be 2.82 billion dollars.

Transportation, accommodation and security will be enormous challenges while competition is to take place in 33 venues overall, of which 18 exist.

Rio will offer prime time broadcasts for US audiences, which should guarantee big TV income for the IOC from US networks.

Chicago, meanwhile, had the blues in one of the biggest IOC election upsets despite Obama's presence to lobby personally before the IOC.

"I came here as a passionate supporter of the Olympics and Paralympics ... and as a proud Chicagoan ... America is ready and eager to assume that sacred trust," he said.

Chicago-born Michelle Obama talked passionately about her youth in the city, her late father and his love for sports, and what Olympics could do to the city.

The blow came four years after New York lost out for 2012 as Obama's presence was seemingly not good enough to sway IOC votes.

Tokyo and Madrid were rated outsiders but former IOC president Juan Antonio Samaranch pleaded his age of 89 as he asked the IOC members to consider voting for Madrid, which nonetheless failed for the third time in the end.  dpa