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! — Donald J. Trump (@realDonaldTrump) March 13, 2018

According to CNN, Tillerson was informed by Chief of Staff John Kelly last week that he would be replaced, though Tillerson wasn't given a timeframe for that transition. Trump and Tillerson have continuously butted heads throughout Tillerson's time as Secretary of State with their policy disagreements including how to respond to North Korea, the Paris climate accord, the Iran nuclear deal and Russian interference in the presidential election. Tillerson also came under fire for reports that he had called Trump a moron. Meanwhile, the president has been criticized for publicly undermining Secretary Tillerson.

In his tweet, Trump also said that Gina Haspel, the current deputy director of the CIA, will take over for Pompeo. Both will need to be confirmed by the Senate.

Trump's use of Twitter is quite different from President Obama's and while many have questioned the content of his tweets and how they impact national interests in the past, some are now calling out his use of the platform to fire high-level officials.