Doctored video of sinister Mark Zuckerberg puts Facebook to the test

Last month Facebook declined to remove a manipulated video of Nancy Pelosi even after it was viewed millions of times

A doctored video of Mark Zuckerberg delivering a foreboding speech has been posted to Instagram, in a stunt that put Facebook's content moderation policies to the test.

Videos known as "deepfakes" use artificial intelligence to manipulate the appearance and voices of individuals, often celebrities, into theoretically real-looking footage. They are likely to become the next wave in the battles over disinformation online.