The World Food Program lacks crucially needed funds to help feed Haiti's poor, and international donors must provide urgent and massive aid, a spokesman for the United Nations agency said on Thursday.

"The situation is particularly serious because 56 percent of the Haitian population was already living with less than one dollar a day," the WFP regional public information officer, Alejandro Lopez, told Reuters.

"We don't have enough food to face the demand and we will need even more funds than what already requested."

He said the agency had a $37.8 million shortfall in the $45 million budget anticipated for this year in the Caribbean nation, where recent food riots killed six people.

The program aims to feed 1.7 million Haitians but predictions show the number needing help to cope with the current food crisis could reach close to 5 million.

The Haitian government and other partners are working on new budget figures that will be presented to donors in the coming days, according to WFP officials.

"We expect donors to be as generous as they have been in the past," said Lopez, who said children, pregnant women and nursing mothers would be given priority during food distributions.

Scores of people were turned away empty-handed from a U.N. food distribution on Saturday in the Cite Soleil, the country's largest slum. There was food for only 1,000 of the nearly 400,000 residents of the infamous shantytown once controlled by heavily armed gangs.

The secretary-general of the Organization of American States, Jose Miguel Insulza, said donors must urgently come to help to the Haitian poor in these difficult times.

"We need to heed the call of the Haitian people facing hunger and hardships," Insulza told Reuters after arriving at the capital's airports on Thursday.

According to figures released by the WFP, 22 percent of Haitian children are underweight because of malnutrition and 9 percent of them suffer acute malnutrition, while 50 percent of pregnant Haitian women are anemic.

At least six people were killed earlier this month during riots and clashes between security forces and demonstrators who were protesting rising food prices and the high cost of living. Lawmakers sought to calm the anger by dismissing Prime Minister Jacques Edouard Alexis, who is expected to be replaced soon.

President Rene Preval announced a 15 percent cut in rice prices and a series of measures to uphold national food production by providing subsidies, credit and technical assistance to farmers.

The Haitian government has also banned any export of rice as officials feared the subsidized rice could be diverted to the neighboring Dominican Republic.

"There was movement on the (Haitian-Dominican) border aimed at exporting the subsidized rice to the other side of the island," said Customs Director-General Jean-Jacques Valentin. "It is forbidden to export rice from Haiti under any pretext."