Donald Trump. Pic/AFP

United States President Trump on Thursday 'fired' his National Security Adviser (NSA), H.R. McMaster and named John Bolton as his successor, according to the White House. In a tweet, the US President made the announcement and said that McMaster had done an 'outstanding job'. "I am pleased to announce that, effective 4/9/18, @AmbJohnBolton will be my new National Security Advisor. I am very thankful for the service of General H.R. McMaster who has done an outstanding job & will always remain my friend. There will be an official contact handover on 4/9," President Trump wrote on Twitter.