Russian gymnast Ivan Kuliak has appeared at a World Cup medal ceremony wearing a 'Z' added to his vest.
The 20-year-old debutant at the event won bronze in the parallel bars competition in Doha.
Kuliak appeared to have taped the letter, which is one of the insignia on Russian military equipment, to the front of his vest.
Ukrainian Ilya Kovtun, who won gold, and silver medalist Milad Karimi, of Kazakhstan, stood next to Kuliak.
Russian athletes are competing at the World Cup under neutral status as part of sanctions imposed by the International Gymnastics Federation (FIG) following the invasion of Ukraine.
Together with their Belarusian counterparts, Russian athletes will not be allowed to take part in FIG competitions from Monday.
Kaluga-born Kuliak became the Russian Junior all-around and floor champion in 2019.
The prospect has won a string of gold medals among a haul of honors at competitions in his homeland.
His third-placed finish in Qatar marked a successful start to his 2022 campaign in his first competition of the year.
In a statement on Friday, FIG confirmed that Russian and Belarusian athletes will not take part in the Acrobatic Gymnastics World Championships in Baku from March 10-13 2022.
The federation said the "exceptional and emergency measures" had been taken "in view of extraordinary circumstances."
"They constitute preventive measures aiming at preserving the integrity of gymnastics, the safety and integrity of members and all athletes and participants, and at fighting against all forms of violence and of sports injustice," it added.
"[We] will continue to monitor the situation closely and may further adapt these exceptional measures according to future developments."