WASHINGTON — President Donald Trump on Thursday publicly pushed back against a characterization by White House Chief of Staff John Kelly that his views on a southern border wall had "evolved" and privately fumed about the episode.

Trump's comments on Twitter came a day after Kelly told Democratic lawmakers that some of the hard-line immigration policies Trump advocated during the campaign were "uninformed," that the United States will never construct a wall along its entire southern border, and that Mexico will never pay for it, according to people familiar with the meeting.

Later Wednesday, Kelly confirmed his comments to Democratic lawmakers during a television interview but attempted to play down any differences with the president while describing him as a willing negotiator as a government shutdown looms.

"He has evolved in the way he looks at things," Kelly told Fox News. "Campaign to governing are two different things, and this president has been very flexible in terms of what's in the realm of the possible."

Trump associates said the president was furious with Kelly both for what he said and for the tone he used, which Trump thought made it appear he was a child who had to be managed. One Trump associate who spoke to the president Wednesday night said Trump thought Kelly's comments made him look bad and that he was giving in to Democrats. The president, this person said, particularly disliked that the word "uninformed" appeared in news reports and has chafed for weeks at the characterization of him as not intelligent and flighty in the best-selling book about his presidency by author Michael Wolff.

The person, who requested anonymity to speak more candidly, said it was "inevitable" for Trump to be angry with his chief of staff and that it was actually surprising that it hadn't happened before. It was a positive sign for Kelly, this person said, that he didn't mention the chief of staff's name explicitly in the tweet. There seems to be no effort afoot though to make any change in the chief of staff position, this person said.

Christopher Ruddy, a Trump friend and president of the conservative media outlet Newsmax, agreed with that assessment.

"The president is pretty happy with his job overall," Ruddy said of Trump. "Trump's the type of guy who will dress you down if he doesn't like what you say, but it's got to be a whole long list of things before he takes action against somebody. Generally, in my personal view, he's very happy with General Kelly, overall."

Kelly had struck a nerve with Trump by speaking out on immigration in particular.

"In President Trump's world, you can have disagreements privately or publicly, but immigration is a hot-button issue for him, and it's something he doesn't like to see disagreements on, especially publicly," Ruddy said. "He knows how important it is to his base."

Another Trump associate familiar with the president's reaction to Kelly said his rage was similar to his response in the summer of 2016 when Paul Manafort, then his chief strategist, told an RNC meeting in Florida that Trump had been playing a "part" on the campaign trail but was starting to pivot toward presenting a more businesslike and presidential "persona."

"Kelly thinks he knows what policies are important and what aren't, but Donald Trump is the president of the United States," said the associate, who also requested anonymity to speak more candidly.

In another tweet Thursday morning, Trump continued to insist Mexico would pay for the border wall.

Kelly's original comments came during a closed-door session at the Capitol on Wednesday with members of the Congressional Hispanic Caucus and House Minority Whip Steny Hoyer, D-Md. Kelly repeatedly said Trump supports enacting permanent legal protections for dreamers and that he has helped the president evolve on immigration policy, according to people there.

Following the meeting, Rep. Luis Gutierrez, D-Ill., one of the participants, put out a statement that Kelly said Trump's views were "not fully informed."

"A concrete wall from sea to shining sea" is not going to happen, Kelly said according to attendees. Instead, "a physical barrier in many places" is what the administration is requesting. Kelly used the term "physical barrier" several times during the meeting, attendees said.

"Concrete wall is not a realistic solution in many places," Kelly said — noting that topography, among other issues, makes building a physical wall difficult along certain parts of the more than 2,100 miles between the United States and Mexico.

Instead, "we need 700 more miles of barrier," Kelly said — a concession that a physical barrier does not need to stretch the entire length of the border.

"Concrete wall would be good in only certain places," he added, saying that manpower and drone technology should suffice in some parts.

Kelly also said there will be no wall "that Mexico will pay for."

Later in the Fox interview, Kelly confirmed that the administration is seeking 700 miles of new wall and reiterated Trump's view that the United States would be able to use a renegotiation of NAFTA to get Mexico to pay for the wall.

"In one way or another, it's possible that we could get the revenue from Mexico, but not directly from their government," he said.

The Washington Post's Ed O'Keefe contributed to this report.