The government of Zambia has asked the United Nations World Food Program to remove thousands of tons of genetically modified food that had been donated to the country. The demand follows a decision last week by the government to refuse donations of so-called GM food.

The World Food Program says the Zambian government has told the agency to empty its warehouses and take all food which has been genetically modified out of the country.

A spokeswoman for the agency, Christiane Berthiaume, says the government has not given it an ultimatum, but she says the World Food Program is preparing to transfer its stock of 15,000 tons to neighboring Malawi and Zimbabwe, which also are facing a food crisis.

Ms. Berthiaume says the World Food Program is in the process of buying 30,000 tons of non-GM food with cash contributions it recently has received. She says some of this food will be brought into Zambia. But she adds that there are 3 million hungry people in Zambia and she is not confident that the agency will be able to get enough food to feed them all.

"It is going to be difficult," said Ms. Berthiaume. "We are going to do our best obviously. We are going to continue to negotiate and talk with the Zambian authorities. We hope that countries that do not produce GM food will come up with contributions in kind or in cash because with cash we can buy."

The United Nations estimates 14 million people in six southern African countries are at risk of starvation. Zambia is the only one of the six to refuse genetically modified food. The other five countries are Lesotho, Malawi, Mozambique, Swaziland and Zimbabwe.

At the end of last month, the Zambian government announced it would not accept donations of genetically modified food. The government made the announcement after a group of its scientists completed a visit to the United States and European countries.

Ms. Berthiaume says on the basis of that trip, the government has concluded that GM food might be toxic and says it wants to continue evaluating the risks.

GM foods are made from crops in which the genetic material has been altered to make them more resistant to insects or diseases. The World Food Program says it considers this food to be safe.