NAIROBI, Kenya — More than 3 million people have died during Congo's civil war, the vast majority from malnutrition and disease, a relief organization said Tuesday.

The International Rescue Committee said in a report that at least 85 percent of the 3.3 million deaths were from easily treatable diseases and malnutrition.

"This is a humanitarian catastrophe of horrid and shocking proportions," George Rapp, president of the New York-based organization said.

Previous IRC studies put the death toll at around 2.2 million.

A UN official dealing with Africa said an accurate account of the number of dead is impossible, but the toll of two million had been widely accepted. The officials spoke on condition of anonymity.

The IRC said the humanitarian disaster has been caused in part by the forced displacement of people fleeing fighting and the collapse of the country's health system.

The Congo war began in August 1998 and at one point drew in armies from six other African nations.

But the rescue committee said there grounds for hope because deaths from violence apparently had dropped by as much as 90 percent since a survey carried out in 2001.

The organization also said a South African-brokered peace process has resulted a power-sharing agreement and the withdrawal of most foreign forces.

But the IRC said fighting continued in eastern Ituri province and urged diplomatic and humanitarian action in the face of "the magnitude of this crisis."