At least three people are feared dead following floods caused by heavy rains that pounded Kenya' capital, Nairobi, for hours.

Among those killed was a police officer who was rescuing trapped families in the Kamukunji area, local media reported.

Authorities are yet to confirm the deaths.

Videos and photos that went viral on social media showed motorists stranded in their cars as the floodwaters submerged various roads.

Parts of the Nairobi Expressway, which links the country's main airport to the capital, were also flooded. Videos posted online by motorists showed cars being redirected by the toll road officers.

Weather experts have said the rains would continue over the next few days.

The Kenya Red Cross has advised motorists and pedestrians to evacuate roads immediately if they sense impending danger.