The sporting world has largely frozen out Russia and its military ally Belarus from international competitions in the wake of the full-scale invasion of Ukraine.

However, athletes from Ukraine and Belarus have been allowed to continue competing as neutrals in several sports, notably tennis and judo.

Belarus' national football teams have also not been suspended from FIFA and UEFA competitions, but must play home matches outside of the country.

In a campaign video, Horuna is seen standing in a gym alleging that Russian and Belarusian athletes are partly responsible for the horrors of the war if they remain silent.

"This is a sports hall where Ukrainian athletes could train," Horuna said.

"However, since Russia unleashed a full-scale war in Ukraine, there has been silence.

"Russian and Belarusian athletes are silent either.

"They pretend as if nothing has happened, and with their silence they support the killing, the destruction and this brutal war.

"Silence settled in the Ukrainian halls.

"However, the athletes of the whole world, should not remain silent.

"Join the fight.

"Share your videos and posts calling a boycott of Russian and Belarusian athletes.

"Post them on social media with campaign hashtags

"Support Ukraine on the sports front!"

The high-quality video was produced by Ukraine's Ministry of Youth and Sports.

Horuna, who joined the Ukrainian military for a period in March, has sought to raise funds to support the wat effort by auctioning the karate-gi he wore when he won a bronze medal at Tokyo 2020, as well as the medal itself.

The 33-year-old plans to use the proceeds from the uniform sale to buy a vehicle for a unit fighting against Russia.

Horuna previously sold the Olympic medal for $20,500 (£16,300/€19,400), though the Japanese national who bought it contacted Horuna to say they wanted to return the medal when the war is over.

A substantial number of International Federations, including the World Karate Federation (WKF), decided to ban athletes from Russia and Belarus outright in response to the war, and following a recommendation from the International Olympic Committee.

The WKF has also moved all events due to take place in Russia or Belarus, including a season-ending Karate 1-Premier League leg first set for Moscow.

The United Nations has recorded at least 5,514 civilian deaths in Ukraine since Russia launched its so-called "special military operation" in Ukraine, although it fears the true figure is far higher.

Millions have also been forced to flee Ukraine to neighbouring countries.