The International Olympic Committee is investigating two Chinese gold medallists who wore badges at the podium featuring an image of the country's former leader Mao Zedong during a medal ceremony.

Gold medal sprint cyclists Bao Shanju and Zhong Tianshi wore the badges during a medal ceremony on Monday, in a potential breach of Olympic rules on the display of political paraphernalia.

An International Olympic Committee spokesman said the Chinese Olympic Committee had been asked to submit a report on the incident.

Article 50 of the Olympic Charter says "no kind of demonstration or political, religious or racial propaganda is permitted in any Olympic sites, venues or other areas".

The rules were eased last month to allow athletes to "express their views" before and after competing, paving the way for athletes to take the knee to highlight racism without facing sanction.

But the ban remains on gestures or statements during competition or at medal ceremonies.

The IOC is also investigating a gesture on the podium by American shotput silver medallist Raven Saunders who had raised her arms in an X above her head. She later explained it was an expression of support for the oppressed.

However, the United States Olympic and Paralympic Committee said the gesture did not breach its rules as it was a peaceful expression in support of racial and social justice and was not disrespectful of other competitors.