At least 21 people have been killed and 60,000 have been made homeless in eastern Kenya after severe flooding, according to the Kenyan Red Cross.
Bridges, roads and buildings have been destroyed by the floods
Reports suggest the main roads linking the Kenyan port of Mombasa to the capital, Nairobi, and to Tanzania have been cut as bridges were washed away.
The flash floods follow unusually heavy rains which are expected to continue.
The country's health ministry warned of possible outbreaks of water-borne disease, notably cholera.
At least six people died at the weekend as they were swept away by flood waters around the port of Mombasa and the north-eastern town of Garissa, officials said.
"We have 60,000 people stranded on higher ground and (major) roads are still inaccessible," Coast Provincial Commissioner, Ernest Munyi, told Reuters news agency. "We are appealing for help in terms of food, medical attention and transportation. The government continues to mobilise available resources to get help to the affected," he said.
Flood waters washed away bridges and roads and destroyed numerous buildings, hampering aid efforts.
"All these people are directly affected or completely cut off and we cannot access them," Abdi Ahmed, the acting disaster response chief at the Kenya Red Cross told AFP news agency.
"We have floods across the country and, since it is still raining, we fear the situation will deteriorate," he said.
In the capital, Nairobi, officials said that overflowing water had blocked the city's drainage system, causing residential areas to flood.