Some Facebook shareholders have added to the growing chorus of criticism directed at chief executive Mark Zuckerberg over his refusal to take action over a controversial post on the world's largest social network site from US President Donald Trump.

Dozens of Facebook employees staged a virtual walk out last week as Zuckerberg defended his decision to not take down Trump’s social media post, which warned against widespread protests that have swept the US following the death of George Floyd. The 46-year-old was an unarmed black man who was killed in police custody in Minneapolis on 25 May.