In Sudan, unusually heavy rainfall in recent days has left tens of thousands homeless in several regions.  As Arjun Kohli reports from our East Africa Bureau in Nairobi, the rains have created another humanitarian crisis in a country already overwhelmed by conflict-driven disasters.

A Sudanese sits amongst the remains of his home following floods in Kassala, near Khartoum, 10 July 2007

Government officials in Sudan's capital Khartoum say 15,000 houses have been destroyed, leaving tens of thousands homeless. Twenty people have been killed in flash floods that have ravaged parts of eastern and southern Sudan.

The floods caused poorly built houses to collapse, and many people escaping the floods are stranded on the roads.

The rains are expected to continue in areas along the Blue and White Niles, south of the capital, as well as in Kassala, in eastern Sudan. 

International agencies say the floods have caused a humanitarian emergency.

An official of the U.N.'s Office for Humanitarian Affairs, Christian Smets, says the biggest problem areas are south of Khartoum.  He says torrential rainfall in the Sudanese capital has not caused extensive damage.  But he says people living in villages outside the city are desperate.

"This year, [there] have been exceptional floods," Smets said. "Livelihoods are being destroyed. They make their livelihoods by small-scale farming.  Livestock, villages, houses being washed away things like that. The international organizations, the humanitarian organizations are gearing up their efforts to help the people affected."

The rains have continued for weeks.  As well as destroying houses, the water collects in stagnant pools that serve as breeding grounds for malaria-carrying mosquitos.  Aid workers say the stagnant water could spurn other water-borne diseases.  

There are also reports that the floods have washed away houses in the war torn area of Darfur, in western Sudan, where over two million people have been displaced since a civil war began there in 2003.

A civil war between north and southern Sudan ended in 2005. 

In other parts of Africa, heavy rains have caused dormant larvae to hatch and swarms of locusts have infested farmland the Horn of Africa region.