Beijing - China organized an exceptional Olympics in which US swimmer Michael Phelps and Jamaican sprinter Usain Bolt stood out, International Olympic Committee president Jacques Rogge said hours before Sunday's closing ceremony at the Beijing Games.

The IOC boss again refused to criticize China in public on issues such as internet access for the media and protest zones, and did not want to comment on China's record gold medal haul either.

He said that the Games had left a great legacy for China in areas such as environment, sports interest and press freedom even though not everything was perfect in relation to the media.

"China has opened for the world to learn all about China, and China all about the world," Rogge told a news conference.

The IOC president also said China had built no white elephants for the Olympics and state-of-the-art arenas such as the Bird's Nest and Water Cube would be used frequently after the Games.

Rogge said London 2012 and other future hosts should not aim to match China's grand scale Olympics but rather look at their own assets.

He said that only six positive doping tests so far at the Games showed that various measures appear to act as a deterrent.

"The IOC is extremely pleased with the organization of the Games. The athletes were at the centre," he said.

Rogge called the eight-time swim gold medallist Phelps and the three-time golden world record sprinter Bolt "icons," but also reiterated his "fatherly advice" to Bolt, who wildly celebrated his 100m victory before crossing the line, to show more respect in the future.

However, the IOC boss also cited as key moments the hug and kiss between medal-winning shooters Natalia Paderina of Russia and Georgia's Nino Salukvadze three days into the hostilities of their countries.

"This kind of sportsmanship and brotherhood" was a sign that the Olympics are not about gold medals alone, said Rogge.

Looking at doping, Rogge said that "more tests and increased penalties" such a ban from the next Olympics were a deterrent for potential cheaters.

The IOC is conducting more than 4,500 tests. So far six cheaters have been caught, with results on Sunday available from samples taken up to last Wednesday. The Athens 2004 Games had 26 positive cases from 3,500 tests.

"The overwhelming majority of athletes is clean. A small minority is positive and taint the whole sport," said Rogge. (dpa)