Why has 'Z' become a Russian pro-war symbol

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.