Carol Bellamy, head of the UN Children's Fund, Unicef, described Aids and the HIV infection as the world's worst undeclared war which had turned sub-Saharan Africa into a ''virtual killing field''.

She said the threat had reached ''monstrous proportions'' and warned that time was running out.

Aids has left thousands of children orphaned

Miss Bellamy said that while an estimated 200,000 people had been killed in conflicts in Africa last year, more than two million had died during the same time from Aids.

And whereas the United States currently spends more than $800m a year fighting HIV infection, the annual figure in Africa - where at least two thirds of the world's HIV infected people live - the figure is only $160m.

Killing field

In one of the hardest hitting speeches at the International Conference on Aids in the Zambian capital Lusaka, Miss Bellamy berated the international community for failing to recognise the economic and social impact of HIV infection.

She said awareness of the fight against Aids in Africa must be raised to that of the continent's military conflicts in Liberia, the Democratic Republic of Congo and Sierra Leone.

"By any measure the HIV Aids pandemic is the most terrible undeclared war in the world, with the whole of sub-Saharan Africa virtually a killing field. The hour is late; time is running out,'' Miss Bellamy said.

''The monstrous proportions of the HIV/Aids pandemic in sub-Saharan Africa show that far from [being] simply another new problem among other development problems, the disease is rapidly becoming a significant and growing threat to peace and stability throughout the entire world."

Miss Bellamy said it was the responsibility of the international community to address the massive inequalities in money available to tackle the disease.

But she also told delegates that Africa must break the conspiracy of silence surrounding Aids among some leaders so that the huge dimensions of HIV infection were not hidden from the people suffering most.