Rule 50 of the Olympic Charter states: "No kind of demonstration or political, religious or racial propaganda is permitted in any Olympic sites, venues or other areas."

The IOC claims this is designed to protect the neutrality of sport and the Olympic Movement, but the USOPC AAC says that athletes "will no longer be silenced".

It is calling for the IOC and International Paralympic Committee to "develop a new policy in direct collaboration with independent, worldwide athlete representatives that protects athletes' freedom of expression at the Olympic and Paralympic Games."

The IOC and IPC "cannot continue on the path of punishing or removing athletes who speak up for what they believe in, especially when those beliefs exemplify the goals of Olympism", the letter states.

It goes on to call for collaboration to create "a new structure that celebrates athletes who speak about issues in alignment with human rights" before referencing directly the plight of Carlos and Tommie Smith.

At the 1968 Olympics in Mexico, men's 200-metre champion Smith and bronze medallist Carlos raised black-gloved fists on the podium in a Black Power salute to protest racism.

Along with Australian runner-up Peter Norman, they also wore badges advocating for human rights.

Both were expelled from the US team at the Games by the USOPC - then called the United States Olympic Committee - for their gesture, which infuriated the IOC but remains one of the most iconic Olympic images.

"The Olympic and Paralympic movement simultaneously honors athletes like John Carlos and Tommie Smith, displaying them in museums and praising their Olympic values, while prohibiting current athletes from following in their footsteps", points out the USOPC AAC letter, which Carlos has signed.

"Carlos and Smith risked everything to stand for human rights and what they believed in, and they continue to inspire generation after generation to do the same. 

"It is time for the Olympic and Paralympic movement to honor their bravery rather than denounce their actions."

The anti-racism protests which have spread across the globe following the police killing of black man George Floyd in the US have led to an increased focus on Rule 50, especially with athletes in sports such as football being allowed and even encouraged to stage such protests of late. 

The Canadian Centre for Ethics in Sport and Global Athlete are among the other organisations to have publicly opposed Rule 50 in recent weeks.

IOC President Thomas Bach has suggested it could be reviewed as part of a consultation process to be conducted by the IOC Athletes' Commission.

Bach said the IOC Athletes Commission' will "have dialogue with athletes around the world to explore different ways for how Olympic athletes can express their support for the principles enshrined in the Olympic Charter in a dignified way".

Under Rule 50 guidelines developed by the Athletes' Commission and announced in January, competitors who protest at "all Olympic venues" - including medal ceremonies, the field of play and the Olympic Village - will face disciplinary action on a case-by-case basis.

The USOPC AAC said its sentiments have been shared with the IOC Athlete Commission.

Last year, hammer thrower Gwen Berry, who raised her fist at the end of a medal ceremony at the Lima 2019 Pan American Games, and fencer Race Imboden, who knelt during a medal ceremony at the same event, were put on probation for 12 months by the USOPC.

The USOPC AAC letter can be viewed in full here.