US President Donald Trump has sacked Secretary of State Rex Tillerson, replacing him with the director of the CIA, Mike Pompeo.
Thanking Tillerson for his service on Twitter, Trump said the new state secretary would do "a fantastic job".
Tillerson, a former chief executive of ExxonMobil, was only appointed to the job just over a year ago.
Tillerson had just returned to the US from his first African tour.
He visited Djibouti and Ethiopia before arriving in Kenya on Friday evening.
Tillerson met President Uhuru Kenyatta at State House on the same day.
He, however, cancelled scheduled events on Saturday on the second day of a visit to Kenya because "he was not feeling well", a State Department spokesman said.
"The secretary is not feeling well after a long couple days working on major issues back home such as North Korea and has cancelled his events for the day," spokesman Steve Goldstein said.
He was also to attend an event to highlight US health assistance in Africa, and meet NASA leader Raila Odinga as well.