U.S. Secretary of State Rex Tillerson cancelled scheduled events on Saturday on the second day of a visit to Kenya because "he is 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 told reporters travelling with Tillerson.
"Some events will go ahead without him, while they are looking at the possibility of rescheduling others," said Goldstein, under-secretary of state for public diplomacy and public affairs at the State Department.
Tillerson, 65, is four days into his first diplomatic trip to Africa, where he has visited Ethiopia, Djibouti and Kenya, and is scheduled to go on to Nigeria and Chad.
During the trip he has also been involved behind the scenes in discussions within the administration on a possible meeting between U.S. President Donald Trump and North Korean leader Kim Jong Un.
A U.S. embassy official in the Kenyan capital, Nairobi, said U.S. Ambassador to Kenya Bob Godec and Kenyan Health Minister Sicily Kariuki would attend events on Saturday morning.
Tillerson had been scheduled to lay a wreath at the site of the 1998 bombing of the U.S. embassy in Nairobi, in which more than 200 people were killed, and attend an event to highlight U.S. health assistance in Africa.