The US president said he "disagreed strongly with many of his suggestions." Bolton, a hawkish neoconservative best known for his "Axis of Evil" views, was a key figure in the US administrations of both Bushes and Reagan.
US President Donald Trump on Tuesday said he fired National Security Advisor John Bolton over strong disagreements.
"I informed John Bolton last night that his services are no longer needed at the White House," Trump said in a series of tweets. "I disagreed strongly with many of his suggestions, as did others in the Administration."
Bolton, however, gave a different story. He said he offered to resign on Monday night but that Trump had told him: "Let's talk about it tomorrow."
Pompeo vs Bolton
Media reports suggested that Pompeo and Bolton were vying for influence with Trump in recent weeks.
At a press conference Bolton was expected to attend before his resignation, US Secretary of State Mike Pompeo said his foreign policy views were different than Bolton's at times.
Treasury Secretary Steve Mnuchin also signaled Trump's openness to a "no preconditions" meeting with Iranian President Hassan Rouhani at the UN General Assembly in New York later this month.
Iranian officials welcomed Bolton's departure. "John Bolton has promised months ago that Iran would last for another three months," Iranian government spokesman Ali Rabiei said in a tweet. "We are still standing and he is gone."
Trump's acceptance of negotiating directly with dictators was frowned upon by Bolton, who has openly backed regime change as a viable option.
When tapped to fill the role, many saw Bolton's views at odds with Trump's protectionist "America First" foreign policy outlook. Bolton often disagreed with Trump's decisions, including on issues such as the withdrawal of US troops from Syria and Afghanistan.