Donald Trump has announced former UN ambassador John Bolton will serve as national security adviser, replacing H.R. McMaster.
McMaster is the latest of several senior officials to leave the White House, following the departure of Secretary of State Rex Tillerson.
Bolton served as a highly controversial ambassador to the United Nations under the George W. Bush administration.
Bolton’s new role will prove controversial since he remains an unapologetic cheerleader of the 2003 Iraq war, which the US president himself once lambasted as “a big mistake”.
Trump recently announced his intention to install CIA Director Mike Pompeo as Tillerson’s replacement, starting in April.
At least a dozen aides to the president have now left their posts in a little over a year.
McMaster said in a statement: “After thirty-four years of service to our nation, I am requesting retirement from the U.S. Army effective this summer after which I will leave public service. Throughout my career it has been my greatest privilege to serve alongside extraordinary service members and dedicated civilians.”
The move was first reported by the New York Times.
NBC News was first to report that the White House was preparing for McMaster’s exit, a move reportedly orchestrated by Chief of Staff John Kelly and Secretary of Defense Jim Mattis.
In response, the Trump administration dismissed NBC’s March 1 report as “fake news” and stressed that McMaster was doing “a great job”.
McMaster’s tenure in the Trump administration was marked by conflict as he repeatedly found himself at odds with the president.
After special counsel Robert Mueller indicted 13 Russians in February, McMaster said there was “incontrovertible” evidence that Russia had moved to influence the 2016 presidential election.
Trump himself has long pushed back against allegations of Russian interference in the election, but recently attempted to blame former President Barack Obama for not doing enough to counter Russian meddling.