The US national football squad kicked off a 12-day training session in Sao Paulo on Tuesday as part of their "dry run" for the upcoming World Cup.

Under tight security, coach Jurgen Klinsmann held an initial practice with his 26 players at the Sao Paulo FC club's training facility, rated as one of the best in Brazil.

The former star from Germany said his squad includes many young players "who have a point to prove, that they can all go to the World Cup".

Klinsmann said he came to Sao Paulo on a scouting tour two years ago and decided that Brazil's economic capital was the best place in terms of hotels and training facility to set up the US base camp for the two-week tournament that will open here June 12.

After conducting daily workouts and two private scrimmages over the next 12 days, the US team plan to play a friendly against South Korea in Carson, California on February 1.

Klinsmann acknowledged that team USA face a tough group against Germany, Portugal and Ghana and must beat Ghana in the opening game in the northeastern city of Natal on June 16.

"We badly need three points against Ghana and one point against Portugal," he said.

Travel to northeastern World Cup venues such as Natal, Recife and Manaus will be a major challenge although American players are used to travel long distances at home, he added.

He also expressed confidence that Brazil will rise to the challenge of hosting their first World Cup since 1950 despite concern about delays in readying stadiums and infrastructure projects.

"I'm sure Brazil will make it work," he said.

As to who will win the World Cup final in Rio's iconic Maracana stadium on July 13, Klinsmann said: "Brazil, Spain and Germany have these expectations...We don't."

But he stressed that the US squad aim to be "in the top 10, 15 in the world" in the future.

"We are not there yet, but we are working on it...It's not going to happen overnight," he told reporters.