Death toll from heavy rain and flooding across Kenya has risen to 186 and an estimated 800,000 people have been affected, the UN humanitarian agency said on Thursday.

Citing figures from the Kenya Red Cross Society (KRCS), the UN Office for the Coordination of Humanitarian Affairs (OCHA) said the number includes about 300,000 who have been displaced and nearly 100 injured, although many of those displaced have begun to return home.

"Children have been severely affected. There are reports of unaccompanied and separated children due to the floods and heightened protection risks for women and girls," OCHA said in its Flash Update.

The heavy downpours that started in April have paralyzed transport in several parts of the country. The weatherman indicates that the current weather pattern may still persist for some time.

According to official statistics, over 739 schools have closed temporarily due to floods, disrupting learning for more than 100,000 children.

The most affected counties by flooding include Garissa, Isiolo, Kisumu, Mandera, Marsabit, Narok, Samburu, Taita-Taveta, Tana River, Turkana, Wajir and West-Pokot, according to the National Disaster Operational Centre.

"Health partners remain concerned regarding the increased risk of health emergencies, including cholera outbreaks in affected areas, due to poor sanitation and lack of access to clean water," said OCHA.