The United Nations estimates that at least 320,000 people have left their homes in Iraq since the U.S.-led invasion, some for temporary quarters elsewhere in Iraq, some for Syria, Jordan and other places, Jan Egeland said.

"That is not irreversible, but the longer it goes, the more you cement the situation," Egeland said in an interview with The Associated Press, citing experience from the Balkans, Lebanon and other ethnic and religiously driven conflicts.

The figure of 100 violent deaths a day comes from checks of morgues in Baghdad and elsewhere by the U.N. and other aid groups, he said." More