Russian gymnast Ivan Kuliak is facing disciplinary proceedings by the International Gymnastics Federation for displaying the letter "Z" on the podium next to a Ukrainian rival in Qatar.
In Russia, the "Z" is fast becoming seen as a staunchly pro-war symbol of President Putin's invasion of Ukraine.
It has been sported by politicians, seen on the sides of cars, vans and advertising hoardings - as well as daubed on bus shelters.
It has even been used by Serbs at pro-Russian demonstration in Belgrade. Photographs have been widely shared on social media.