“I informed John Bolton last night that his services are no longer needed at the White House. I disagreed strongly with many of his suggestions, as did others in the Administration,” Trump tweeted.
“I asked John for his resignation, which was given to me this morning,” the president said, adding that he was aiming to announce a replacement next week.
Bolton seemed to take a parting shot at his boss, immediately responding on Twitter: “I offered to resign last night and President Trump said, ‘Let’s talk about it tomorrow.’”
Bolton also texted U.S. media outlets to say he resigned on his own.
The move came as a surprise, with the White House putting out an advisory just an hour before the Trump announcement saying that Bolton would be taking part in a media briefing along with Secretary of State Mike Pompeo and Treasury Secretary Steven Mnuchin.
Bolton also continued to post administration policy on social media right up until the Trump announcement.
However, Trump has previously hinted at his disagreements with Bolton on foreign policy, and observers had regularly noted that the two made an odd couple, with the president more isolationist and the national security adviser an interventionist.
“John Bolton is absolutely a hawk. If it was up to him, he’d take on the whole world at one time.
“But that doesn’t matter because I want both sides,” Trump told broadcaster NBC in June.
Bolton, Trump’s third national security adviser, appeared to be waging numerous battles within the White House, most recently over Afghanistan and North Korea, that seemed at odds with the president’s wishes.
Bolton was also behind the hard-line approach to countries such as Iran and Venezuela.
The national security advisor comes from the wing of the Republican Party more aligned with the policies of the George W Bush administration, in which he also served. He is often seen as a proponent and even an architect of the invasion of Iraq in 2003.
When not in government, Bolton has worked for conservative think tanks.
While Trump himself has led recent policies on Iran, and to some extent Venezuela, he is more reluctant to deploy U.S. troops abroad and is actively seeking to reduce the military’s presence in places like Afghanistan and Syria.
U.S. media reported in recent weeks that Bolton and Trump were bitterly fighting over the approach to Afghanistan, as the president tried to work out a peace deal with the Taliban.
That process has since broken down, with Trump calling it “dead”.
Trump has also sought better relations with Russia, against the advice of establishment figures, though ties with Moscow are tense and the current administration has actually increased sanctions on the rival power.
Mira Ricardel, who served as a deputy to Bolton until late last year, was also sacked from her job after she got into a disagreement with first lady Melania Trump, in a highly unusual public spat between the wife of the president and a top-level security official.
The Trump administration’s first national security adviser, Michael Flynn, is currently tied up in legal battles over lying to the FBI about contacts with Russian officials and is due to face sentencing in December.
Bolton is the latest figure to exit the White House amid disputes with the president.
Notably, Jim Mattis quit as defence secretary last year over disagreements on Syria, and Trump abruptly fired Rex Tillerson as secretary of state as well as his attorney general, Jeff Sessions.
The president is on his seventh communications chief and has also pushed out two chiefs of staff. The current chief of staff is only in an acting role. (dpa/NAN)