The IOC sent a six-point letter, a copy of which was obtained by The Associated Press, to the national Olympic federations in response to their request for interpretations of Rule 51.3 of the Olympic charter.

That rule states "no kind of demonstration or political, religious or racial propaganda is permitted in any Olympic sites, venues or other areas."

The letter expanded on the rule, saying, "The conduct of participants at all sites, areas and venues includes all actions, reactions, attitudes or manifestations of any kind by a person or group of persons, including but not limited to their look, external appearance, clothing, gestures, and written or oral statements."

"As in all Olympic Games, such conduct must also, of course, comply with the laws of the host state.

The IOC has long relied on Rule 51.3 as its guiding principle for Olympic participants, but has been pressed of late to offer more guidance in light of recent protests over Tibet and China's crackdown on dissenters.

In April, IOC president Jacques Rogge said IOC officials will use common sense to decide whether athletes are simply celebrating victories or using them to make political statements.

"Freedom of expression is something that is absolute. It's a human right. Athletes have it," Rogge said.

The IOC letter said that, indeed, Olympic athletes are free to express their opinions, so long as those expressions are in compliance with the Olympic charter.

It gave athletes permission to answer questions on any topic in media interviews and said the rule relied on the "common sense of all athletes and other participants in showing respect for the dignity of all fellow athletes, including those of the host country."

The letter reiterated the IOC's often-stated position that the Olympics are a ‘great sports festival’.

"They are not a stage for different kinds of political statements about issues such as armed conflicts, regional differences, religious disputes and many others," it said.

This position differs with the actual history of the games, which have been marked by political gestures, boycotts and violence during the past four decades.

One of the iconic Olympic pictures of the 20th century was that of American sprinters Tommie Smith and John Carlos on the medals stand in 1968 after the men's 200 metres, raising their black-gloved fists and bowing their heads in a racial protest aimed at American society during the playing of US national anthem.

That type of display would presumably be forbidden in Beijing, though the short letter did not outline possible sanctions for violating Rule 51.3.

The letter asked national organising committees to contact their athletes with the new information.