By the BBC's David Bamford

The United Nations has opened its annual global appeal in which it is calling for $3bn in aid next year to help some 50 million people it says are in dire straits.

Once again this year, most of the countries in the greatest need are on the continent of Africa, where the impact of poverty and conflict has been aggravated by the world's highest infection rates of Aids.

Afghanistan has been the 'in' cause this year

Every year brings humanitarian crises in the world, some attract a spontaneous outpouring of global aid - currently Afghanistan is in vogue, and before that the former Yugoslavia.

But other equally or more serious situations can be all but ignored. This annual process sponsored by the UN and known as the consolidated inter-agency appeal, is an attempt to steer global funding where it is most needed.

Last year's appeal for $2.5bn has had to be bumped up to over $4bn because of Afghanistan and the unanticipated famines in southern and north-east Africa.

For 2003, the UN's opening bid is for a further $3bn.

Global campaign

As with last year, priority is being given to African states: Angola; the Great Lakes countries - Rwanda, Burundi and DR Congo; Eritrea; Ethiopia; Somalia and Sudan; west and southern Africa.

Several Asian states are also being targeted: Afghanistan; Tajikistan; North Korea and Indonesia.

Elsewhere, the Palestinian territories and Chechnya are on the list of priorities.

The UN, in launching this appeal simultaneously in eight capitals, says it is the most efficient means to ensure that funding is distributed on the basis of need rather than on the level of media attention.