Dmitry,

The problem with internet is that with too much information available, everything becames very difficult to find, but I clearly remember many analysts saying that this was a possibility, and I remember arguing others in other forums about it. May be something like this is what you want?

"In addition to possible ongoing guerrilla action by Saddam Hussein’s supporters, U.S. occupation forces would likely be faced with competing armed factions among the Sunni Arab population, not to mention Kurd and Shiite rebel groups seeking to break away from any ruler in Baghdad. This could lead the United States into a bloody counterinsurgency war. Without the support of other countries or the United Nations, a U.S. invasion could leave American forces effectively alone enforcing a peace amidst the chaos of a post-Saddam Iraq."

From http://www.globalpolicy.org/security/issues/iraq/attack/2002/08fallacies.htm#7

>Could you show ONE link to a news analysis or an article published before the invasion that indicates a threat of possible violence of iraqis-against-iraqis?