BEIJING - China completed its stint as Olympic Games host yesterday with a superstar-studded closing ceremony that capped a 16-day pageant of state-of-the-art logistics and astounding athletic feats, set out for a curious world. The games did little, though, to erase concerns about the emerging superpower's approach to human rights.

Tenor Placido Domingo was on hand, joining a Chinese soprano in a lyrical duet. Soccer icon David Beckham and graying Led Zeppelin guitarist Jimmy Page were there, helping London take the reins as host-to-be of the 2012 Olympic Games.

Yet even as the International Olympic Committee was praising itself for awarding Beijing these Olympics, the U.S. Embassy urged China to free foreign activists jailed for protesting at the games. China, the embassy suggested, should have used its moment in the global spotlight to show "greater tolerance and openness."

China nonetheless achieved its paramount goals: a dominant effort by its athletes to top the gold-medal standings for the first time and near-flawless organizing that showcased world-class venues and smiling volunteers.

As a bonus, not just one but two athletes gave arguably the greatest performances in Olympic history - Michael Phelps with his eight gold medals in swimming, Jamaica's effervescent Usain Bolt with three golds and three world records in the sprints.

Delighted with the on-field competition, the IOC insisted its much-debated selection of Beijing back in 2001 had been vindicated.

"Tonight, we come to the end of 16 glorious days which we will cherish forever," IOC President Jacques Rogge told the capacity crowd of 91,000 at the National Outdoor Stadium, and a global TV audience. "Through these games, the world learned more about China, and China learned more about the world."

"These were truly exceptional games," he said, before declaring them formally closed.

The head of the Beijing organizing committee, Liu Qi, said the games were "testimony to the fact that the world has rested its trust in China." He called them "a grand celebration of sport, of peace and friendship."

American rower Jennifer Kaidom, of West Leyden, N.Y., said the games exceeded her expectations.

"We were prepared for smog, pollution, demonstrations, but everything has gone very smoothly," she said.

Rogge acknowledged that China, despite promises of press freedom during the games, continued to block access to numerous politically oriented Web sites, including those related to Tibet and the outlawed spiritual movement Falun Gong.

However, he contended that media restrictions were looser during the Olympics than beforehand, "and so we believe the games had a good influence." *