Donald Trump hits out at 'witch hunt' after ex-FBI boss chosen to head Russia investigation

US president Donald Trump has said the appointment of a special counsel to investigate allegations that his campaign collaborated with Russia to sway the 2016 election is "the single greatest witch hunt of a politician in American history".

This is the single greatest witch hunt of a politician in American history!

— Donald J. Trump (@realDonaldTrump) May 18, 2017