Brasília, Brazil—Brazil's president unveiled the 2016 Olympic torch with a vow to overcome the Latin American giant's mounting problems -- ranging from massive corruption to street violence -- in time for a "historic" Rio games.

The white torch, inlaid with blue and green waves, was shown off at a ceremony in the capital Brasilia. Next May, officials announced, it will depart on a tour of 300 cities and towns across the vast country, before arriving for the opening Olympic ceremony on August 5 at Rio de Janeiro's Maracana stadium.

"There will be around 12,000 torchbearers and the flame will travel along approximately 20,000 kilometers (12,430 miles) of Brazilian roads," as well as racking up thousands of air miles, the Rio2016 organizing committee said.

For Rousseff, beset by plunging popularity, the ceremony was an opportunity to reignite optimism over the "honor and pride" at being the first South American country to host the Olympic Games.

"We are now 399 days from the opening of the Olympic Games and on August 5, the whole world will look at us, will see the Olympic flame light up," she said. 

- Troubled times - 

Coming on the back of the 2014 football World Cup in Brazil, the 2016 Olympics had been seen underlining the rise of this country of 200 million as a major economic and political power.

However, a steady drip of bad news has since eroded Brazil's standing and sent Rousseff's own ratings plunging to nine percent.

The country's biggest company, state-owned oil major Petrobras, is at the center of a huge corruption scandal, scaring investors and tainting Rousseff, even if she has not been implicated.

Confidence in Brazil's ability to stage the world's biggest sporting event has also been shaken, despite the overall success of the World Cup.

Worries range from acute pollution in the Rio de Janeiro bay where the sailing competition will take place to a resurgence of violent crime in the picturesque and vibrant, but sometimes chaotic place dubbed by Brazilians "the marvelous city."

Rousseff, known widely here simply as Dilma, said the games would show what Brazil can do.

"We are confident that we can meet the challenge before us. We will put on a historic Olympics," she said.

Brazilians, said the president, should take inspiration from their athletes.

Athletes train "not to give up, to conquer, with much effort and much work," she said.

"Brazil has this characteristic. I am sure that the Olympics is a symbolic moment for us. We will show what this country is made of," she said.

- Olympics fever? - 

For a country known for samba, caipirinha cocktails and the famed Rio carnival, Friday's unveiling ceremony was distinctly lacking in exuberance.

Rousseff was flanked by dozens of politicians in suits on a theater stage where the audience was also largely comprised of people in business suits, clapping politely during her speech.

However, officials believe that the torch's journey around the country will get the whole country fired up.

The route will take in "close to 90 percent of the Brazilian population," the tourism ministry said.

As a result, "the Olympic Games are a golden opportunity not just for Rio de Janeiro but for Brazil to promote itself as a tourist destination for Brazilians, rather than an international market," Tourism Minister Henrique Eduardo Alves said.

"Everyone will feel they are taking part," Rousseff said.