President Donald Trump continues the shakeup of his White House national security team with the appointment of John Bolton, former US ambassador to the UN to replace H.R McMaster as national security adviser. Bolton is a renowned security commentator with hawkish views. Trump tweeted the news Thursday night adding: 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.