Logistics and shopping centres in and around the Ukrainian capital have been reduced to rubble, Klitschko says.
He also speaks of mounting civilian deaths, mass destruction, a catastrophic humanitarian toll, and reports of genocide during the Russian invasion of his country, which began more than seven weeks ago.
In the interview, Klitschko thanks all democratic nations involved in aiding his country and calls for more support for an embattled Ukraine at war with Russia.
Click on the audio player above to hear the interview.