The growth in international talent means the US men's basketball team face a "tough challenge" to win Olympic gold, head coach Mike Krzyzewski said.

"Basketball around the world has exploded. Thirty per cent of the NBA are international players, and many of the teams we face will have a starting five of five NBA players," Krzyzewski said in Macau, where the gold medal favourites will play exhibition games against Lithuania and Turkey before travelling to Beijing.

"It will be a tough challenge for us."

The US have won 12 Olympic men's titles but their supremacy has slipped in recent years.

Spain won men's gold at the 2006 world championships behind inspired Los Angeles Lakers player Pau Gasol, who will be key to Spanish ambitions in China. Argentina, who took gold at the 2004 Athens Olympics, will also be a serious threat to American hopes of redemption.

Team USA finished with bronze four years ago and were third at the 2006 worlds.

Previous US teams have been all-star squads tossed together just weeks before the Games and Jerry Colangelo, managing director of the US team, said "that was good enough, but that's not the case anymore."

The players "wanted to see this thing turned around because there is pride in representing our country and the commitment that was made three years ago means that the core players have been together for the past three years, and that's a big difference," he said.

NBA top scorer LeBron James, who was wearing a USA basketball shirt printed with the words "Together we rise", said confidence would be the key.

"Every time we step onto the court we know we have the talent and we know we have the strength to go out and be the best team. So, we have to be confident to go out there and play the way we want to play," he said.

Krzyzewski later clarified that "we're trying to be very confident. That doesn't mean over-confident.

"We don't have anything to be complacent about."

James will play in Beijing, despite an earlier right ankle injury that he described as "healthy".

Basketball is extremely popular in China and will be one of the hottest tickets at the Beijing Games.

The host team have been given a huge boost by the return of towering Houston Rockets centre Yao Ming after he broke a foot in an NBA game in February.

Krzyzewski said China merited respect.

"I would think that they'd be better than they were the last time we played them. They will be a foe - especially (since) they are our first game in the Olympics."

The US and Chinese teams meet on August 10.