The United States says it is donating $127 million in aid for southern African countries where the worst drought in decades is affecting millions of people.

Monday's announcement comes as the Southern African Development Community calls for more than $2 billion in aid for drought-hit member states.

The U.N.'s World Food Program says the El Nino-induced drought has devastated crops and caused harvests to fail. It has declared southern Africa a level-three emergency, its highest level.

WFP says 18 million people need emergency food assistance in seven severely affected countries: Lesotho, Madagascar, Malawi, Mozambique, Swaziland, Zambia and Zimbabwe.

Aid officials say the drought is also a health crisis. One-third of the world's HIV-infected population lives in southern Africa, and the U.N. says people cannot take treatment on an empty stomach.