Trump's national security adviser H.R. McMaster resigns - to be replaced by hard-line Bolton

Donald Trump's national security adviser H.R. McMaster is to go.

Trump has repeatedly clashed with McMaster, a respected three-star general, and talk that McMaster would soon leave the administration had picked up in recent weeks.

Lieutenant General H. R. McMaster, a battle-tested Army officer, was appointed Trump's national security adviser only last year. He will resign and be replaced by John R. Bolton, a hard-line former United States ambassador to the United Nations, White House officials said today.

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.

— Donald J. Trump (@realDonaldTrump) March 22, 2018

McMaster's departure follows Trump's dramatic ouster of Secretary of State Rex Tillerson last week. It also comes after someone at the White House leaked that Trump was urged in briefing documents not to congratulate Russian President Vladimir Putin about his recent re-election win. Trump did it anyway.

McMaster was brought in to stabilise a turbulent foreign policy operation after Trump's first national security adviser, Michael Flynn, was dismissed because he did not tell White House officials, including Vice President Mike Pence, about the full extent of his contacts with Russian officials.

McMaster has done "an outstanding job & will always remain my friend", Trump tweeted.

Bolton, who has advocated using military force against Iran and North Korea and has taken a hard line against Russia, will take over April 9, Trump said. The 69-year-old has long been a polarising figure in Washington foreign policy circles, and is Trump's third national security adviser in 14 months.

Probably the most divisive foreign policy expert ever to serve as UN ambassador, Bolton has served as a hawkish voice in Republican foreign policy circles for decades. He met Trump and White House chief of staff John Kelly early this month to discuss North Korea and Iran.

McMaster's resignation is the latest in a long line of staff to leave the White House under Trump's presidency. Here are some of the notable ones:

March 22, 2018: National security adviser, H.R. McMaster

March 16, 2018: Deputy Director of the FBI, Andrew McCabe

March 13, 2018: Secretary of State, Rex Tillerson

March 12, 2018: President Trump's personal assistant, John McEntee

March 6, 2018: Head of the National Economic Council Gary Cohn

February 28, 2018: Communications director Hope Hicks

February 27, 2018: Deputy communications director Josh Raffel

February 7, 2018: Staff secretary Ron Porter

December 13, 2017: Communications director for the White House Office of Public Liaison Omarosa Manigault Newman

December 8, 2017: Deputy national security adviser Dina Powell

September 29, 2017: Health and Human Services Secretary Tom Price

August 25, 2017: National security aide Sebastian Gorka

August 18, 2017: Chief strategist Steve Bannon

July 31, 2017: Communications director Anthony Scaramucci

July 28, 2017: Chief of staff Reince Priebus

July 21, 2017: Press secretary Sean Spicer

May 30, 2017: Communications director Michael Dubke

May 9, 2017: FBI Director James Comey

February 13 2017: National security adviser Michael Flynn

-AP