The U.S. President, Donald Trump on Tuesday, 10th September, said he had asked John Bolton, his national security adviser, to resign, citing strong differences of opinion with his hawkish assistant.

“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.