US President Donald Trump abruptly announced on Tuesday that John Bolton is no longer his national security advisor and he was asked to resign.

Taking to Twitter, Trump wrote, “I thank John very much for his service. I will be naming a new National Security Advisor next week”.

The tweet came just one hour after the White House press office said Bolton was scheduled to appear at a press briefing alongside Secretary of State Mike Pompeo and Treasury Secretary Steve Mnuchin.

When Mike Pompeo was asked during a press briefing whether he or Steve Munchin were surprised that Bolton was fired, Pompeo said, “I’m never surprised.”

In response to Trump, Bolton also took to Twitter, saying “I offered to resign last night and President Trump said, ‘Let’s talk about it tomorrow.”

The chaos and infighting that swirls around Trump’s White House was on immediate display – Bolton immediately disputed the president’s account of his departure.

Trump said he will make a decision next week but given the President’s unpredictable nature, sources warn that he could choose someone who is not under discussion right now.

The President has had three national security advisers — Bolton, Michael Flynn and H.R. McMaster. He has summarily fired a secretary of state, Rex Tillerson, by tweet after undercutting the former ExxonMobil CEO for months.

Bolton’s departure comes as tensions with Iran are escalating in the Persian Gulf, North Korea continues to develop its weapons capabilities, arms control experts are warning of a potential nuclear arms race with Russia and trade tensions with China are intensifying, while Trump is discussing a drawdown of forces in Afghanistan.