The United States said Friday it is airlifting more than 200 tons of food supplements to Niger to help children at risk of starvation. It is the second U.S. airlift of its kind in less than a month to Niger, where drought and a locust plague wiped out much of the past year's crops.

The assistance being flown to Niger on two chartered jumbo jets is not traditional food aid, but a high-energy supplement aimed at saving children who may be near death because of the country's food crisis.

U.S. officials say about 34,000 children in Niger have been identified by the U.N. children's agency UNICEF as being at imminent risk, but that the supplements, if administered promptly, could reverse their condition within just a few days.

The officials said the emergency aid, which was to have been flown from France to Niger's capital Niamey on Friday, brought to total amount of U.S. food assistance to Niger this year to $14 million.

Niger has been the hardest hit among several countries in West Africa's Sahel region affected by drought and a locust plague which ravaged harvests last October including fodder for livestock.

The crisis, the worst in the area in two decades, has also affected Burkina Faso, Mali, Mauritania and Senegal to varying degrees.

At a news briefing, Ed Fox, Assistant Administrator of the U.S. Agency for International Development (USAID) said the most urgent need will likely be in the next two months, given that rainfall in much of the area has improved for the current growing season:

"Indications are that the rains earlier this year were quite adequate," said Mr. Fox.  "There is hope that the harvest this year will be at least at the same levels of the last five years and perhaps in a much larger amount. So we are hoping that will indicate that the most desperate time will be between now and September at some point, when they begin to bring in the harvest in the country, and that will alleviate a lot of the underlying problems."

The U.S. aid official defended the American response to the situation amid criticism of donor countries by some relief groups, who say the Sahel situation went unnoticed amid the world's focus on the Asian tsunami disaster.

Mr. Fox said U.S. aid officials were among the first to identify and warn of a looming crisis in the Sahel last year, and that the United States has been the single-biggest contributor, with $127 million in emergency aid provided to the region.

Mr. Fox said between two and three million people, about 20 per cent of Niger's population, are affected by the drought and that 800,000 require direct outside food assistance.

A report this week from USAID said the agricultural shortfall in Niger has caused market prices of cereal grains there to soar by more than 75 percent.

It said the loss of nearly 40 percent of the country's fodder crops from last year has driven down livestock prices as herders are forced to sell undernourished cattle in order to buy food.