The Ethiopian government and aid agencies estimate that 4.6 million people in the Horn of Africa country need emergency food aid to tide them through to the next harvest in November.

Another 5.7 million who receive food and cash under a regular welfare programme live in areas where drought is biting and need extra help.

"Already for some kids ... it's too late, but it's not too late for many, many other children who need assistance until the next harvest comes in," said Sonali Wickrema, who designs programmes in Ethiopia for the U.N. World Food Programme (WFP).

"We want rapid assistance now in order to prevent large-scale and long-term damage," she said.

The Ethiopian government says 75,000 children are already suffering from the most severe form of malnutrition.

The government and aid agencies put out a call in mid-June for $325 million to deal with the failure of the shorter of two rainy seasons combined with soaring food and fuel costs.

WFP country director Mohamed Diab said donors had only agreed to provide half of that so far, and urged them to give the rest without waiting for the emergency to become more acute.

"Given the fragile and critical nutritional situation in the country, if such resources don't come on time ... we will see the situation worsening beyond the current level," Diab warned.

He said food aid would take two to three months to arrive in the country. Due to dwindling stocks, WFP has already cut cereal rations for July by a third.

High prices and a lack of food supplies in Ethiopia are forcing WFP to bring in food aid from outside the country, from places such as South Africa and the Black Sea region.

The agency says the cost of white maize, the staple food for most poor Ethiopians, has risen more than 150 percent on Ethiopian markets in the past year, and grain has become so scarce that prices for most domestically produced cereals are higher than imported supplies.

Aid agencies have warned about similar problems in nearby countries dealing with the overlap of drought and high global food prices -- Somalia, Kenya, Djibouti and parts of Uganda.

In addition, Ethiopia has used most of its emergency food reserves to feed around 3 million poor people in urban areas over the past 18 months, according to WFP.

Wickrema said the failure of the March-May rains had begun to cost lives in Ethiopia. She said WFP did not have an accurate death toll, but it had probably not yet reached the hundreds.

The longer of the country's two rainy seasons has now started in some areas, but some aid agencies fear it will not be enough for a good harvest.