Whether John Bolton quit as national security adviser or whether President Trump fired him, no one was too surprised that the relationship ended.

They spoke on the phone Monday night and argued over Afghanistan and Bolton's opposition to Trump's since-scuttled plan to host Taliban leaders at Camp David to broker a peace deal.

But they differ on what happened next. 

Trump tweeted Tuesday that he "informed John Bolton last night that his services are no longer needed at the White House."

"I disagreed strongly with many of his suggestions," Trump continued, adding Bolton to a long list of aides fired via tweet.

But this time, there was return fire just a few minutes later.

"I offered to resign last night and President Trump said, 'Let's talk about it tomorrow,'" Bolton retorted via tweet.

Bolton's departure was announced barely 90 minutes before he was to hold a briefing at the White House with Secretary of State Pompeo and Treasury Secretary Steve Mnuchin, both of whom had repeatedly clashed with the national security adviser. The briefing went ahead anyway.

Now, names are being discussed to replace Bolton.

While Trump claimed he would make a decision "next week," there does not appear to be a short list at the moment. White House deputy press secretary Hogan Gidley told reporters Tuesday that Charles Kupperman, who was Bolton's deputy, will serve as acting national security adviser until a replacement is picked.

Given Trump's unpredictable nature, sources warn that the President could choose someone who is not being discussed right now to become his fourth national security adviser in less than three years.

But in the short term, these are some of the people who have been mentioned as possible candidates, CNN reported.

Brian Hook, US Special Representative for Iran and senior policy adviser to Mike Pompeo: Hook's name is being floated as a possibility to replace Bolton, according to three sources familiar with the discussions.

He is interested in and campaigning for the job, according to one source familiar with the process. Hook started at the State Department under Secretary Rex Tillerson and remained a key member of the team when Pompeo took over. He recently traveled with Trump's senior adviser and son-in-law, Jared Kushner to the Middle East trip and is well liked at the White House, another source told CNN. Hook was tapped by Pompeo to lead the State Department's efforts on Iran.

Ricky Waddell, Major General in the United States Army Reserve who served for a year as Trump's Deputy National Security Adviser to Trump: White House officials are discussing Waddell as an option to replace Bolton as well, according to three sources familiar with the ongoing talks. Waddell left the administration last year and he was close with Trump's former Chief of Staff John Kelly.

Others include Steve Biegun, the U.S. Special Representative to North Korea; Rob Blair, national security adviser to acting chief of staff Mick Mulvaney; Richard Grenell, U.S. ambassador to Germany; Pete Hoekstra, U.S. ambassador to the Netherlands; Keith Kellogg, national security adviser to Vice President Mike Pence, and others.