John Bolton is out as White House national security adviser.
On Tuesday President Donald Trump tweeted bluntly that he called for his resignation due to numerous policy disagreements.
"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."
Bolton seemed to counter the president on Twitter, saying he "offered to resign last night and President Trump said, "Let's talk about it tomorrow."
Bolton, a leading foreign policy hawk widely known to have pressed the president for a harder line on issues such as North Korea. Bolton, also a chief architect of Trump's strong stance on Iran, had advocated a tougher approach on Russia and Afghanistan.
Trump had sometimes joked about Bolton's image as a warmonger, reportedly saying in one Oval Office meeting that "John has never seen a war he doesn't like."
His ouster comes after Trump canceled a peace talks with the Taliban at Camp David. Sources say Bolton was not on board with the talks.
The president said he'd name a replacement next week.
Bolton was Trump's third national security advisor after Michael Flynn and General HR McMaster.