Combo photo shows Rex Tillerson (L) and Mike Pompeo. [File photo]

U.S. President Donald Trump announced on Tuesday on his Twitter that Rex Tillerson will no longer serve as Secretary of State, and he will be replaced by CIA Director Mike Pompeo.

"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!" he wrote.