Zambia has refused emergency food aid from the United States despite being one of the countries worst affected by famine in Africa.

Zambian officials say the supplies of maize from the US come from genetically modified crops and that they are concerned the food could contaminate local agriculture.

The fact that the people are starving doesn't mean that we should allow them to eat what they don't know

Zambian high commissioner in UK

Zimbabwe and Mozambique have also expressed concern about offers of genetically engineered grain.

The World Health Organisation has certified the grain for human consumption and says it does not constitute a danger to people's health.

Thirteen million people in southern Africa are in need of food aid because of a prolonged drought, many of them in Zambia.

Appeal for money

Zambia's High Commissioner in the United Kingdom, Silumelume Mubukwanu, told BBC Radio 4's World Tonight programme that there was still insufficient knowledge about the effects of GM foods.

The threat of famine is something we know, we know what happens when people don't eat - they die

Andrew Natsios Agency for International Development

"The fact that the people are starving doesn't mean that we should allow them to eat what they don't know," he said.

"My government is saying to all governments of good will - please give us money to buy the ordinary food that people in Zambia eat, or buy it for us on our behalf," he added.

'No evidence'

However, the director of the Washington-based Agency for International Development - Andrew Natsios - is urging the Zambian authorities to reconsider their stance.

He told the BBC that there was no scientific evidence that the seed had caused any health problems anywhere in the world, adding that he and his family had been eating it at home for seven years.

He said that whatever concerns Zambia had about GM food should be seen in the context of the situation.

"The threat of famine is something we know, we know what happens when people don't eat - they die," he said.

Lesotho, Swaziland and Malawi have already accepted the aid.

But Zimbabwe and Mozambique said they will only accept the grain if it is milled to avoid contamination of their own crops.