The UN warned on Tuesday that flash floods could hit East Africa over the coming months and deal a devastating blow to hundreds of thousands of people who are already reeling from severe drought.

The UN's humanitarian coordination office predicted that the El Nino climate pattern in the Pacific basin could trigger heavy rain in the Horn of Africa after the region was hit one of the worst droughts in a decade.

- El Nino could create in the coming weeks and months extremely serious floods in the Horn of Africa with mudslides, destruction to crops, and illnesses linked to water - said Elisabeth Byrs, spokeswoman for the UN's Office for the Coordination of Humanitarian Affairs.

The UN estimates that 750,000 people in Kenya and some 450,000 people in Somalia's Shabelle and Juba river basins could be affected, while 50,000 people in Tanzania would be at risk of a repeat of the devastating 2006-07 floods.

Some areas might see water reserves replenished by the expected torrential rains and a recovery in their parched pastures, according to OCHA.

But the downpour is not expected to relieve food shortages in the region until harvests in 2010, it added.

British charity Oxfam said last month that more than 23 million people face severe hunger and destitution across East Africa because of the direct or indirect effects of the drought, which has lasted five years in some areas.