President Trump today

Members of the North Korean government are reading Michael Wolff’s “Fire and Fury” to understand President Donald Trump, according to a longtime former negotiator who travels to Pyongyang frequently to meet with members of the Kim Jong Un's regime.

 “They were very keen to study Donald Trump when I was there in December,” Jonathan Powell told Christiane Amanpour in London.

Powell, who is the former chief British negotiator on Northern Ireland and former chief of staff to Tony Blair, now runs a private firm, Inter Mediate.

“They were reading ‘Art of the Deal,’ and wanted to discuss the book and what it showed about the President," he said.

“When I went back at the beginning of this year, they were reading ‘Fire and Fury’ – all on PDFs, not buying the book itself, and trying to discuss what that told them about Trump too.”

President Trump offered another guarded respond to warnings from North Korea Thursday, saying it's possible the upcoming summit with Kim Jong Un doesn't happen.

"We may have the meeting. We may not have the meeting. If we don’t have it that will be very interesting," Trump said in the Oval Office.

He said preparations are underway for the summit, including direct dealings with North Korea to make arrangements.

"We’ll see what happens," he said ."We are dealing with them now."

He said the harshening of tone from North Korea began after Kim met for the second time with Chinese President Xi Jinping, but didn't offer a theory as to why.

"You have to want to do it. With deals…you have to have two parties that want to do it," Trump said. "(Kim) absolutely wanted to do it. Perhaps he doesn’t want to do it."

North Korea threatened earlier this week to cancel the June 12 summit between President Trump and Kim Jong Un.

Today, Trump said North Korea hasn't told his administration anything.

"Well, nothing has changed with North Korea that we know of. We have not been told anything," Trump said. "If it doesn't, that's fine. We have not been told anything. We're just reading story like you are. We've heard certain things from South Korea. We'll see what happens."

"If the meeting happens, it happens. If it doesn't, we go on to the next step."

White House press secretary Sarah Sanders said President Trump was "very clearly referring to MS-13 gang members who enter the country illegally" when he talked about "animals" illegally crossing the US-Mexico border.

"This is one of the most vicious and deadly gangs that operates by the motto of rape, control and kill," Sanders said. "If the media and liberals want to defend MS-13 they're more than welcome to."

Sanders went on to describe in graphic terms several violent crimes she said were carried out by MS-13 gang members.

"It took an animal to stab a man 100 times and decapitate him and rip his heart out," Sanders said. "It took an animal to beat a woman they were sex trafficking with a bat 28 times, indenting part of her body. And it took an animal to kidnap, drug nand rape a 14-year old Houston girl."

The White House said Thursday that President Trump's lawyers determined it wasn't necessary to include reimbursement payment to Michael Cohen on last year's financial disclosure form.

"That was addressed in the financial disclosure. That is something that would be determined by White House counsel," press secretary Sarah Sanders said.

In the form released on Wednesday, a footnote indicated that Trump's lawyers didn't believe it was necessary to list the payment, but were doing so in the interest of full transparency.

On the one-year anniversary of special counsel Robert Mueller's appointment, White House press secretary Sarah Sanders said the President still believes the investigation is a "witch hunt."

"The President knows that there was no collusion in the campaign and he has been quite clear about this. It's gone on for over a year and they've found no evidence," Sanders said in response to a question from CNN's Jeff Zeleny."

She added that Trump still "strongly feels it's a witch hunt" and said the White House and the President could not be "more clear" about that view.

Earlier today, Trump took to Twitter today to voice his frustrations over the probe.

Read his tweets below:

Press secretary Sarah Sanders, pressed on why a planned joint press conference was scrapped on Thursday, said President Donald Trump would likely take questions in the Oval Office later this hour.

"The President will have press at his event here shortly," Sanders told CNN's Jeff Zeleny. "And he's likely take a few questions at that event."

Trump had been expected to hold a news conference with NATO Secretary General Jens Stoltenberg during his visit to the White House, but the event wasn't on his schedule when it was released last Wednesday.

The White House moving forward with preparations for the June 12 summit with Kim Jong Un, despite North Korea's threats to cancel the meeting.

"We're continuing to move forward in preparations," White House press secretary Sarah Sanders said.

"And the President, as we've said all along will be prepared and ready to meet."

Asked if North Korea was playing a game, Sanders said, "You'd have to ask North Korea what game they're playing."

The White House said on Thursday that if the FBI had an informant within the Trump campaign it should be investigated.

"If there’s any truth to that it should certainly be looked into," press secretary Sarah Sanders told reporters.

She said she hadn't spoken to the President about the issue, and wouldn't engage in hypotheticals about whether the report changes Trump's thinking about firing Robert Mueller.

Earlier Thursday, Trump tweeted: "Wow, word seems to be coming out that the Obama FBI “SPIED ON THE TRUMP CAMPAIGN WITH AN EMBEDDED INFORMANT.” Andrew McCarthy says, “There’s probably no doubt that they had at least one confidential informant in the campaign.” If so, this is bigger than Watergate!"