The chart titled "Index of Civil Conflict" shows a colour-coded bar with "peace" marked on the left and "chaos" on the right. An arrow puts the current situation inside the red area on the far right, much closer to chaos than peace.

US commanders have acknowledged violence in Iraq is at its highest level since US-led forces invaded in 2003 and toppled Saddam Hussein, but they have repeatedly said a full-scale civil war can be averted.

The chart, however, indicates a steady shift toward chaos since the bombing of a Shia shrine in the town of Samarra in February. The graphic was prepared by US Central Command, which oversees operations in Iraq, and shown at a briefing on October 18, the New York Times said.

The chart also shows a slight shift toward chaos over the previous week. But White House spokesman Tony Snow said the graphic was only a snapshot taken at the height of violence during the Muslim holy month of Ramadan.

"If you got the same report last week, you would have found out the national sectarian incidents from the 21st to the 27th dropped 23 percent, casualties nationwide dropped 23 percent, incidents of sectarian violence in Baghdad dropped 23 percent, sectarian killings in Baghdad dropped 41 percent," he said.

Central Command said it would not comment on classified material but a spokesman said its top commander, Gen. John Abizaid, and other leaders had been discussing "the reality of the situation in Iraq" for months.