Crowds eager to catch a glimpse of US President Barack Obama thronged the 1998 bomb blast site where he laid a wreath on Saturday.
They did not see him as he was whisked away shortly after, to State House for talks with President Uhuru Kenyatta.
There was a scuffle after which a civil rights activist, donning the colours of the national flag, was escorted away from the August 7th Memorial Park at the Railways roundabout.
The activist had been entertaining the crowd, which chanted pro-Obama slogans, in an area where tight security was maintained.
Nandi Hills MP Alfred Keter was among those waiting to see the US President at the venue.
So far, Obama has had dinner with his relatives and officially opened the 6th Global Entrepreneurship Summit taking place at the UN headquarters in Gigiri.
He is expected to give two public addresses, at Kenyatta University and Safaricom Stadium Kasarani, on Sunday.