NAIROBI, March 10 (Xinhua) -- U.S. Secretary of State Rex Tillerson canceled a day of events scheduled here for Saturday because of illness, the U.S. State Department said.

Tillerson fell ill after having gone two days without sleep and worked on major issues such as the Democratic People's Republic of Korea (DPRK), Undersecretary of State Steve Goldstein told reporters travelling with Tillerson.

Goldstein said some events may be rescheduled for later during his trip, including a wreath-laying ceremony at the site of the 1998 bombing of the U.S. Embassy in downtown Nairobi.

Besides, Tillerson had also planned to attend an event Saturday organized by the President's Emergency Plan for AIDS Relief, or PEPFAR, which went on without him.

He plans to spend another day in Nairobi before heading for Chad's capital N'Djamena and Nigeria's Abuja next week.

The top U.S. envoy on Tuesday kicked off his visit to five African countries, namely Ethiopia, Djibouti, Kenya, Chad and Nigeria. The five-stop trip has so far coincided with two major events in Washington: One is President Donald Trump's decision to impose tariffs on steel and aluminum; the other is Trump's announcement that he is ready to meet with the DPRK's top leader Kim Jong Un by May.

Tillerson has been engaged with all these issues in real time, Goldstein said.