However, pictures and and video shown later were not convincing.
Skepticism is the correct approach towards all kinds of announcements by the Russian authorities and Russian media.
Although one might ask "But why would they lie"?, a more appropriate question is "Why wouldn't they"?
Paraphrasing words form one of Roy Lichtenstein's paintings, we should ask:
BUT... IN A POST-1917 WORLD HOW CAN WE BE SURE?