The United Nations is appealing for just over $4bn (£3.25bn) to fund humanitarian operations in Sudan and neighbouring countries hosting refugees.

The UN describes human suffering of epic proportions in Sudan.

More than nine million people have been displaced by fighting between rival military leaders which began last year.

Ethiopia, Chad and Egypt are struggling to support refugees from Sudan. UN aid agencies say half of the country's population - 25 million people - is in need of assistance. Eighteen million face acute food shortages.