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Wladimir Klitschko, the former boxing champion and brother of the mayor of Kyiv, has described the "worst nightmare" of seeing the aftermath of civilian killings in Bucha.
Talking to Yahoo News France, the former heavyweight champion said: "I've seen many many civilians that have been tortured before they got killed."
He said his experience was like a nightmare, but where a nightmare is "something that comes at night and goes because there is the next day" the reality of war never stops.
Klitschko, who has become the righthand man of Vitali, the mayor of Kyiv, said: "I couldn't imagine seeing so much blood of young women, men, elderly, on their knees with their hands tied behind their back and executed by being shot in the head."
Klitschko has been actively involved in the defence of Kyiv, but as Russian forces pulled back from the city, Ukrainian forces have uncovered evidence of mass killings and brutality inflicted upon the civilian populations in the occupied areas.
So far, more than 400 bodies have been discovered in mass graves in Bucha, with local authorities saying they expect to find more.
The evidence of atrocities in Bucha, a city on the outskirts of Kyiv, shocked the world and led to international calls for Vladimir Putin to face a war crimes investigation.
Klitschko said the things he'd seen he couldn't have imagined as being his worst nightmare.
He said he saw cars fully of dead civilians which had the word 'children' written on them.
He said he saw cars with civilians in them flattened by tanks left in the road.
"War in my mind is the worst nightmare, I couldn't imagine that war is so reckless, so inhuman."