Lusaka, Zambia ? With his people growing ever more desperate, Zambia’s president has become the latest southern African leader to declare the regional food shortage a national disaster.

Two U.N. food agencies estimate 10 million people are on the brink of starvation a number that doesn’t take into account the 4 million believed threatened in Zambia.

Homeless street children in downtown Harare, Zimbabwe, collect drinking water from a water main. In Malawi, Zimbabwe, Lesotho and Swaziland, about 10 million people are at risk of starvation, the World Food Program and the Food and Agriculture Organization announced late Wednesday.

In a nationwide address broadcast on television and radio late Wednesday, President Levy Mwanawasa appealed for immediate international aid, saying his country would run out of corn its staple by August.

In some areas, people already have resorted to eating wild roots, and most children do not get even a single meal a day.

The U.S. government announced Thursday it was donating 8,500 tons of food aid to Zambia worth $2.3 million. Far more was needed, said Judith Lewis, regional director for the U.N. World Food Program.

“We urgently appeal to other donor nations to provide assistance and help avert a major humanitarian crisis,” she said.

Officials blame the food shortage on drought, floods and other disastrous weather that has ravaged two successive harvests. Government corruption and mismanagement have exacerbated the crisis, aid agencies say.

Precise numbers for those needing help in Zambia and Mozambique both badly affected by the crisis were not yet available.

But about 10 million people in four other southern African nations Malawi, Zimbabwe, Lesotho and Swaziland are at risk of starvation, the World Food Program and the Food and Agriculture Organization announced Wednesday.

Though crops were harvested in April and May, the food agencies worry that the tiny amounts reaped could start running out in the next few weeks.

“It could turn (into a famine) if adequate measures are not taken immediately,” said Liliana Balbi, the FAO official responsible for Southern Africa. “The numbers of people requiring assistance are enormous.”

The region needs 1.2 million tons in emergency aid and about 4 million tons to make it through the year, according to the U.N. agencies.

Aid officials were also worried the food shortages would worsen the impact of HIV, which infects an estimated 5 million people in the six countries.

“It’s just really an explosive situation, when you have those two things combined,” said Brenda Barton, a WFP spokeswoman. “In a food crisis, the people that die the first are the weak. The weak in southern Africa are people with HIV/AIDS.”

Some of the suffering has been self-inflicted.

Malawi declared a state of disaster in February. Yet the government inexplicably sold off its 167,000 ton emergency grain reserve last year just before the crisis started. It is still investigating what happened to the proceeds.

In Zimbabwe, a nation used to selling crops to its neighbors in times of need, the food shortage was exacerbated by the government’s seizure of white-owned commercial farms for redistribution to landless blacks, the WFP said.

Earlier this month, Zimbabwe’s Finance Minister Simba Makoni said the country needed to raise as much as $30 million for urgent imports of food.

U.N. officials estimate it could cost the cash-strapped government $345 million to feed its 13 million people this year.