Three people, including a British national, are being questioned after the seizure of nearly 100kg of cocaine at Kenya's main seaport.
The drugs were seized by US drug enforcement administration officials and police from a container delivered by ship from Brazil, a senior Kenyan police official said.
A British national and two Kenyans are being questioned, the official said.
The drugs were seized last week in containers supposedly carrying sugar destined for Uganda, officials said.
The seizure was a rare one in Kenya, which the UN says has become a cocaine distribution hub in recent years.
Traffickers from South America are said to take advantage of Nairobi's extensive air links to Europe and Asia.