After months of disputes with Secretary of State Rex Tillerson, President Trump removed him Tuesday and nominated CIA Director Mike Pompeo to head the State Department.

White House officials later said that a Tillerson aide was also fired for giving reporters differing accounts of how the secretary of State learned of his fate. The two officials spoke on condition of anonymity because they were not authorized to speak publicly about the move.

The officials said they are bracing for more staff changes, citing Trump's comment to reporters Tuesday as he prepared to fly to California: "I'm really at a point where we're getting very close to having the Cabinet and other things that I want."

Tillerson, who said Trump called him hours after he tweeted an announcement about Pompeo's nomination, told reporters his last day would be March 31, and he pledged an "orderly and smooth transition."

Trump told reporters he made the decision himself on Tillerson himself, citing disagreements with the secretary of State that included North Korea diplomacy, steel and aluminum tariffs, and the Iran nuclear agreement.

"I think Rex will be much happier now," Trump said.

Tillerson, whose voice cracked at times during a brief statement at the State Department, did not take questions from reporters.

Steve Goldstein, the Tillerson aide who was fired, said Tillerson wanted to stay as secretary of State.

As for Pompeo, Trump praised his new nominee's "tremendous energy, tremendous intellect," and added that "we’re always on the same wave length. The relationship has been very good and that’s what I need as Secretary of State."

Trump said in a written statement that, at the State Department, Pompeo "will continue our program of restoring America’s standing in the world, strengthening our alliances, confronting our adversaries, and seeking the denuclearization of the Korean Peninsula."

Speaking later with reporters before his departure on a trip to California, Trump said he got along with Tillerson, but they disagreed on things. Trump cited the Iran nuclear deal in particular: "I think it's terrible, he thinks it's okay." He also complimented Tillerson for "his commitment and his service, and I wish him well. He’s a good man.”

A State Department official sent out a terse reaction to the sudden news — and was later fired for it.

Goldstein, undersecretary for public diplomacy, said Tillerson "did not speak to the President and is unaware of the reason" for the decision.

"The Secretary had every intention of staying because of the critical progress made in national security," Goldstein said. "He will miss his colleagues at the the Department of State and the foreign ministers he has worked with throughout the world."

Hours later, Goldstein was fired for suggesting Tillerson learned of his dismissal by tweet.

The two White House officials said chief of staff John Kelly spoke with Tillerson on Friday and Saturday about the change.

“It was clear on Friday,” one of the two officials said.

The State Department said Tillerson did not speak to Trump himself — something White House officials confirm — and that the secretary didn't know about the final decision until the tweet.

Tillerson’s final departure date has yet to be determined, the officials said.

In the meantime, Deputy Secretary of State John Sullivan will serve as acting secretary of State.

In a written statement put out by by the White House, Pompeo said that, if confirmed, "I look forward to guiding the world’s finest diplomatic corps in formulating and executing the President’s foreign policy."

In his time at the CIA, the former Kansas congressman said, "I have worked alongside many remarkable Foreign Service officers and Department of State leaders serving here in the United States and on the very edge of freedom."

Gina Haspel, currently deputy director of the CIA, will become the agency's first woman director of the CIA.

A 30-year veteran of the CIA, Haspel said, "I look forward to providing President Trump the outstanding intelligence support he has grown to expect during his first year in office."

Both Pompeo and Haspel must be confirmed by the Senate.

The administration's critics described Tillerson's abrupt dismissal as another sign of administration disarray. "The instability of this administration in just about every area weakens America," said Senate Minority Leader Charles Schumer, D-N.Y. “If he’s confirmed, we hope that Mr. Pompeo will turn over a new leaf and will start toughening up our policies towards Russia and Putin.”

The decision ends a tumultuous tenure for Tillerson, who often seemed at odds with Trump or out of the loop altogether.

Trump’s tweet Tuesday came the day after Tillerson blamed Russia for an assassination of an ex-spy in London — something the White House had specifically declined to do just hours before.

After the Tillerson announcement, Trump said on Tuesday that it "sounds to me like it will be Russia based on all the evidence they have," and that the United States will condemn the Russians if the British present sufficient evidence. Trump said he will speak today with British Prime Minister Theresa May.

A former Exxon executive, Tillerson has had business dealings with Russia, a source of some controversy when Trump nominated him to head the State Department. A special counsel is investigating potential ties between Trump's 2016 presidential campaign and Russians who sought to influence that race via hacked emails and fake news.

Last Thursday, Tillerson said it would be premature for Trump to hold talks with North Korean leader Kim Jong Un. Later that evening, Trump said he would meet Kim by May to discuss the future of North Korea's nuclear weapons program.

Last year, Tillerson said the United States should talk with North Korea, which Trump quickly shot down.

Tillerson also opposed Trump's decision this month to impose tariffs on certain steel and aluminum imports.

At one point last year, Tillerson reportedly called Trump "a moron" after a national security meeting.