United States President Donald Trump named formed US Ambassador to the United Nations John Bolton as his new National Security Advisor. Bolton will replace Lieutenant General HR McMaster, who took charge in February 2017. The announcement came after weeks of speculation about McMaster’s future.

Trump wrote on Twitter that Bolton will take over on April 9. “I am very thankful for the service of General HR McMaster who has done an outstanding job and will always remain my friend,” the president said in a tweet. In 2017, just before McMaster’s appointment, Trump had called him “a man of tremendous talent and tremendous experience”.

McMaster, a three-star general who was expected to move into a four-star position, will retire from public life, AFP reported. “After thirty-four years of service to our nation, I am requesting retirement from the US Army effective this summer after which I will leave public service,” he said. “Throughout my career it has been my greatest privilege to serve alongside extraordinary service members and dedicated civilians.”

Bolton’s appointment has been fiercely opposed by many people, including those within Trump’s inner circle. He has been a vocal advocate of the Iraq war and has called for preemptive strikes against North Korea and Iran.

Democratic Senator Edward Markey said Bolton’s appointment was “a grave danger to the American people and a clear message from President Trump that he is gearing up for military conflict”.

McMaster’s exit is the latest in a string of high-profile departures from the White House. Others who have either resigned or been sacked in March include Chief Economic Adviser Gary Cohn and Secretary of State Rex Tillerson. National Security Advisor Michael Flynn resigned in February 2017, White House Chief of Staff Reince Priebus in July 2017, and Chief Strategist Steve Bannon in August 2017.