Sudan is the biggest focus of the U.N. appeal, issued to governments on Monday. It wants $930 million for humanitarian work in 2008 in the country where violence and upheaval continues in the Darfur region.

The U.N. request for funds includes Sudan's neighbour Chad as well as Uganda, Zimbabwe, the Central African Republic and Ivory Coast. The U.N. and its aid partners are also seeking funds for the West African region under the appeal.

In addition to the $3.8 billion humanitarian appeal, compiled with 188 aid agencies worldwide, the U.N. typically issues "flash" appeals for emergency funds after natural disasters such as earthquakes and floods.

In 2007, donor countries committed $3.3 billion to the combined regular and flash funding sought by the U.N. for humanitarian work -- some 66 percent of the amount sought, compared with 63 percent in 2006 and 55 percent in 2005.

The United States and Britain were among the biggest donors of emergency aid in 2007, though Norway, Sweden and Ireland gave more as a percentage of their gross domestic product, the United Nations said in a statement.