Islamabad ? The United Nations is appealing for $543 million to ease what it describes as the “incredible suffering” of refugees from Pakistan’s war against Taliban militants.

The U.N. launched the appeal Friday in the Pakistani capital, Islamabad.

Martin Mogwanja, a U.N. official coordinating the humanitarian effort, said the size and speed of the displacement was extraordinary and had caused great suffering.

Pakistani officials say they have registered about 1.9 million people fleeing the fighting in the Swat Valley area since security forces launched an offensive last month.