Wladimir Klitschko, the former world heavyweight champion, has appealed to the world to stop the conflict in his country Ukraine and prevent a humanitarian catastrophe, vowing to fight with his brother Vitaly, the former world heavyweight champion and current mayor of Kiev, against the Russian invasion.
"I am addressing the whole world to stop this war started by Russia," Vladimir said - in a video posted on the Internet.
"There is no time to wait because it will lead to a humanitarian catastrophe. You need to act now to stop the Russian aggression in any way possible; it may be too late in an hour or by tomorrow," he added.
Earlier this month, Vladimir joined the Ukrainian Reserve Army, noting at the time that his love for his country was the motive for its defense.
Russian forces invaded Ukraine early Thursday in what President Vladimir Putin called a "special military operation".