James, coming off his first NBA title with Miami, and Bryant are joined by 2008 gold medal-winning teammates Carmelo Anthony, Chris Paul and Deron Williams on the squad again guided by Duke University coach Mike Krzyzewski.
NBA scoring champion Kevin Durant and Oklahoma City teammate Russell Westbrook, who lost to Miami in the NBA Finals, are also joined by 2010 world championship teammates Tyson Chandler and Kevin Love, two vital big men for the Americans.
With those nine in place, US officials had the task of selecting the last three pieces of the puzzle - filling out the squad Saturday with Blake Griffin, Andre Iguodala and James Harden.
"We projected we would have difficulty getting down to a roster of 12, regardless of the number of injuries that have taken place, because they are such an outstanding group of people and athletes," said Jerry Colangelo, the USA Basketball chairman.
"The final selections keep us in concert with our game plan to have athleticism, versatility and strong depth on our roster. I think our final roster epitomises all of that."
Missing out were Eric Gordon, Rudy Gay and top draft selection Anthony Davis of New Orleans.
Krzyzewski echoed Colangelo's comments on the difficulty of selecting the team, despite injuries that ruled out such NBA stars as centre Dwight Howard, guards Derrick Rose and Dwyane Wade, and forward Chris Bosh. Griffin, slowed by a knee injury in the NBA play-offs, demonstrated his return to health with a dunking display after Saturday's practice.
Harden, who earned the NBA's Sixth Man of the Year award for top reserve, gives the United States a scoring threat off the bench while Iguodala brings a strong defensive presence.
The Americans remain short-handed at centre, where Howard started in 2008 with Bosh as his backup. With Chandler the only true centre remaining, some less experienced players will be called on at the position.
Colangelo alluded to the size disadvantage the Americans are expected to face when he noted that Griffin's size as well as his talent was a factor in his selection.
"He brings bulk, and he's done well in the NBA guarding big centres," Colangelo said.
The US training camp in Las Vegas will run through Thursday, ending with a game against the Dominican Republic.
The Americans then train for three days in Washington before facing Brazil and then train two days in Manchester, England, before taking on the British Olympic squad.
Twenty years after the original US Olympic Dream Team played in Barcelona, the latest incarnation of US NBA Olympic talent will return for exhibition games against Argentina on July 22 and Spain on July 24, the latter a showdown between the Olympic gold medal favourites.
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