"Many families are surviving on just a 20-litre jerry can of water for three days. This is equivalent to 830 ml, or three glasses of water, per person per day for drinking, cooking and washing," the British-based agency said.

"Oxfam's assessment team also gathered reports of people being forced to drink their own urine because of the desperate thirst the drought has caused," its report added.

Some people were forced to trek 70 km (44 miles) to find water in temperatures of up to 40 degrees Celsius (100 Fahrenheit), it added.

"Our assessment shows people in Somalia having to walk the equivalent of almost two marathons to collect water because nearby sources are now just cracked earth," it said.

"The burden is worst for women on whom the responsibility of weekly trips to collect water often falls."

KENYANS BURIED ALIVE

Oxfam said it was launching emergency water operations to help up to 200,000 vulnerable Somalis and their animals, particularly in southern regions near the border with Kenya.

"The situation is as bad as I can remember. Some people are dying and children are drinking their own urine because there is simply no water available for them to drink," Somali village elder Abdullahi Maalim Hussein was quoted as saying.

The Horn of Africa nation of about 10 million people has been without a functioning government since warlords overthrew former dictator Mohamed Siad Barre in 1991.

Roaming militia have been targeting aid consignments.

Across east Africa, hundreds of people, and tens of thousands of livestock, are believed to have died from hunger and thirst since the drought began in late 2005.

As well as Somalia, millions are affected in Kenya, Ethiopia, Eritrea, Tanzania and Burundi.

The drought is likely to persist at least until early April, according to the World Meteorological Organisation.

The increasingly desperate measures being taken across the region were illustrated by the reported death of four Kenyan women buried alive in a well.

They were digging ever deeper after walking 10 km (six miles) because a local river and water-point had dried up.

"Water scarcity occasioned by the hard-hitting drought had greatly affected the villagers of Lolita and its environs, causing them to risk in their search of water," Kenya's daily Standard said, quoting local police chief Bernard Muli.

"As the water table went further down, the women would scoop more sand to harvest water. They were unaware that the walls of the well were getting weaker," said Muli, who heads police in the arid northern Turkana district.