The outgoing secretary of state said he’s delegating responsibilities to Deputy Secretary of State John Sullivan by the end of Tuesday after being fired by Trump.
“What is most important is to ensure an orderly and smooth transition during a time that the country continues to face significant policy and national security challenges,” Tillerson said.
Tillerson said he will be formally stepping down from his post at the end of the month.
Trump announced Tillerson’s removal on social media earlier in the day, adding that CIA Director Mike Pompeo would be his replacement.
“Mike Pompeo, Director of the CIA, will become our new Secretary of State. He will do a fantastic job! Thank you to Rex Tillerson for his service! Gina Haspel will become the new Director of the CIA, and the first woman so chosen. Congratulations to all!”
Gina Haspel will take over as director of the CIA, Trump said.
Tillerson’s firing comes after the now-former secretary of state returned to the U.S. from a shortened trip to Africa.
In a statement, the president said he’s “confident” Pompeo “is the right person for the job at this critical juncture.”
“He 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,” Trump said in the statement. “His experience in the military, Congress, and as leader of the CIA have prepared him well for his new role and I urge his swift confirmation.”
Tillerson said Tuesday that work remains to “respond to the troubling behaviour and actions on the part of the Russian government.”
WATCH: Donald Trump says he’s closer to getting ‘the cabinet I want,’ following the firing of Rex Tillerson
“Russia must assess carefully as to how its actions are in the best interest of the Russian people in the world more broadly,” Tillerson said. “Continuing on their current trajectory is likely to lead to greater isolation on their part, a situation which is not in anyone’s interest.”
In October, NBC news reported that Tillerson called the president a “moron,” something Tillerson never actually denied. Tillerson continued to insist his relationship with the president was solid and brushed off rumours of strain between them.
On Oct. 1, Trump took to Twitter saying “the media has been speculating that I fired Rex Tillerson or that he would be leaving soon – FAKE NEWS!”
“He’s not leaving and while we disagree on certain subjects, (I call the final shots) we work well together and America is highly respected again!” Trump tweeted.
A senior White House official told Reuters news agency Trump had asked for Tillerson’s resignation on Friday, but did want not to announce it while he was on a trip to Africa.
Under Secretary of State Steve Goldstein said in a statement that Tillerson “had every intention of remaining” in his position and did not speak with Trump on Tuesday morning.
“The Secretary did not speak to the President this morning and is unaware of the reason, but he is grateful for the opportunity to serve, and still believes strongly that public service is a noble calling and not to be regretted,” Goldstein said.
Hours after his statement, Goldstein was also fired.
Speaking with reporters before boarding Air Force One, Trump said that Tillerson will be “much happier now,” and he appreciates his service. The president said he and Tillerson had been “talking about this for a long time,” and they had disagreed on issues like the Iran deal.
“We got along actually quite well but we disagreed on things,” Trump said. “When you look at the Iran deal, I think it’s terrible, I guess he thought it was OK. I wanted to either break it or do something and he felt a little bit differently.
“We were not really thinking the same. With Mike, we have a similar thought process,” the president said.
–with a file from the Associated Press