US shot putter Raven Saunders has risked disciplinary action after making the first podium protest of the Olympic Games.
The 25-year-old African-American athlete crossed her arms in an "X" gesture during Sunday's medal ceremony at the Olympic Stadium after claiming silver in her event earlier in the day.
US media outlets reported that Saunders said her gesture was made in solidarity with "oppressed people".
After clinching her silver medal on Sunday, Saunders said she wanted to represent "people all around the world who are fighting and don't have the platform to speak up for themselves."
Saunders' protest is the first test of International Olympic Committee (IOC) rules which ban protests of any kind on the medal podium at the Olympics.
The IOC tweaked its rules regarding athlete protests ahead of the games, saying that peaceful protests before competition would be allowed.
However the Olympics governing body has maintained a strict rule against protesting on the medal podium.
The IOC is looking into the gesture and is in contact with World Athletics, the international governing body for the sport, and the United States Olympic and Paralympic Committee, IOC spokesman Mark Adams told a news conference on Monday.
Updated IOC guidelines released last month say that disciplinary consequences for protests will be "proportionate to the level of disruption and the degree to which the infraction is not compatible with Olympic values."
The United States Olympic and Paralympic Committee said before the Games it will not sanction its athletes for protesting.