Former pro boxer Wladimir Klitschko has called on the world to 'act now' to stop the war in Ukraine.
Russia invaded Ukraine on Thursday (24 February), sparking international shock and condemnation.
Ukrainians are now battling to defend cities, which have been targeted by missile strikes and shellings, with the UK and 26 other nations agreeing to send more weapons and aid to the country.
Klitschko - whose brother Vitali is the mayor Kyiv - has now called on the 'entire world' to take decisive action to end the war.
In a video posted on Instagram, the 45-year-old said: "I'm Wladimir Klitschko, and I'm addressing the entire world to stop this war that Russia has started.
"Just today, civilians were shot by the rockets, with special operations, civilians getting killed. And it's happening in the heart of Europe.
"There is no time to wait because that's going to lead to a humanitarian catastrophe.
"You need to act now to stop Russian aggression with anything you can have now. In an hour, or tomorrow, is going to be too late.
"Please, get into action now. Don't wait. Act now. Stop this war."
Earlier today (Saturday 26 February), brother Vitali - who was also a heavyweight champion boxer - said that a missile hit an apartment building on the south-western outskirts of Kyiv, near Zhuliany airport.
He also imposed a longer curfew in the capital, from 5pm until 8am, and 'all civilians on the street during the curfew will be considered members of the enemy’s sabotage and reconnaissance groups'.
In the wake of the courage and leadership shown by the brothers, Arnold Schwarzenegger labelled them both 'heroes'.
In a tweet, the actor said: "Vitali and Wladimir @Klitschko, I am thinking of you, my friends. You were my heroes in the ring and you’re my heroes now."
In a post on Instagram, the 74-year-old said he was behind the Ukrainian people during this dark time.
He said: "My thoughts are with the Ukrainian people. I have been asked to do several interviews, but I believe the news should continue to focus on what's happening on the ground - on the tragedy that has broken our hearts and on the courage of the Ukrainian people that has inspired us.
"I am not a foreign policy expert, so I will leave the analysis to smarter people than me. I do know what it's like to grow up after a war, in an occupied country, and I know that in war and its aftermath, no one wins. Everyone suffers.
"War has a way of breaking the winners along with the losers.
"I have Ukrainian friends and fans and I have Russian friends and fans. As far as I can tell, none of them want this.
"I hope sanity will eventually prevail and end this unnecessary war before too many lives are broken. In the meantime, I stand with the people of Ukraine.
"I share your grief and your hope for peace. You inspire me with your bravery and your humanity in the face of this nightmare.
"God bless you."
If you would like to donate to the Red Cross Emergency Appeal, which will help provide food, medicines and basic medical supplies, shelter and water to those in Ukraine, click here for more information.
Featured Image Credit: Instagram/Wladimir Klitschko
Topics: World News