Parallel development of an intercontinental ramjet cruise missile that the
West was unaware of until after the end of the Cold War

This looks like something out of 50's sci-fi movie:
https://www.youtube.com/watch?v=po2BPfbfKCc

Like the Navaho, it had its teething problems:
https://www.youtube.com/watch?v=sUhGUOagcuQ
https://www.youtube.com/watch?v=7agFl4dGiIw
https://www.youtube.com/watch?v=yP0FGbTe3LE

More details: http://fas.org/nuke/guide/russia/icbm/930600-cruise.htm

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