He also argued that the invasion was a “a very necessary and important job” and that people in Eastern Ukraine were “welcoming the liberators with flowers”.
However, Professor Michael McFaul, a former US Ambassador to Russia, slammed the corporation for interviewing Mr Milonov.
He said: “If it was September 1, 1939, would you put on the air a member of the Nazi Party.
“To try and explain this ridiculous absolute falsification of history and information that we just heard from Mr Milonov.
“I am wondering if we are doing a service for the world by giving him a voice on the BBC.”
Professor McFaul, who was ambassador in Moscow from 2012 to 2014, was interviewed after Mr Milonov and was aghast that the BBC had allowed his “propagandist” views to be broadcast.
He said: “I don’t like to be on the news with an utter propagandist who is uttering nonsense about what is happening in Ukraine.
“There are no flowers being thrown in front of tanks.
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Mr Milonov has also organised raids on gay clubs in the city, reports show.