The events in Iraq over the last few days do not show a new pattern. Rather, the clashes represent an intensification of sectarian and ethnic strife that some insurgent groups have long provoked in an effort to create a level of civil conflict that could paralyze political progress, divide the new armed forces, and either drive the United States out or deprive U.S. forces of American support.

As the United States and the coalition forces phased down their role, and a sovereign Iraqi government increased its influence and power, insurgents increasingly shifted the focus of their attacks to Iraqi government targets, as well as Iraqi military, police and security forces. At the same time, they stepped up attacks designed to prevent Sunnis from participating in the new government and that increased the growing tension and conflict between Sunni and Shiite, and Arab and Kurd.

There are no clear lines of division between insurgents, but the Iraqi Sunni insurgents focused heavily on attacking the emerging Iraqi government, while Islamist extremist movements used suicide bomber attacks and other bombings to cause large casualties among the Shiite and Kurdish populations -- sometimes linking the attacks to religious festivals or holidays and sometimes to attacks on Iraqi forces or their recruiting efforts. They also focused their attacks to strike at leading Shiite and Kurdish political officials, commanders and clergy.

Targeting other groups like Shiites and Kurds, using car bombings for mass killings, hitting shrines and festivals forces the dispersal of security forces, makes the areas hit seem insecure, undermines efforts at governance, and offers the possibility of using civil war as a way to defeat the coalition and the Iraqi interim government's efforts at nation building.

For example, a step up in Sunni attacks on Shiite targets after the January 30, 2005, election, led some Shiites to talk about "Sunni ethnic cleansing." This effect was compounded by bloody suicide bombings, many of which had some form of government target but killed large numbers of Shiite civilians. These attacks resulted in the discovery of 58 corpses dumped in the Tigris, and 19 bodies of national guardsmen, who were mostly Shiite, in a soccer stadium in Haditha. The attacks also included a bombing in Hilla on March 1, 2005, that killed 136 -- mostly Shiite police and army recruits.

Similar attacks were carried out against the Kurds. While the Kurds maintained notably better security over their areas in the north than in the rest of the country, two suicide bombers still penetrated a political gathering in Irbil on Feb. 1, 2004, killing at least 105. On March 10, 2005, a suicide bomber killed 53 Kurds in Kirkuk. On May 3, 2005, another suicide bomber -- this time openly identified with the Sunni extremist group Ansar al-Sunna -- blew himself up outside a recruiting station in Irbil, killing 60 and wounding more than 150 others. At the same time, other attacks systematically targeted Kurdish leaders and Kurdish elements in Iraqi forces.

By May 2005, Shiites had begun to retaliate, in spite of efforts to avoid this by Shiite leaders, contributing further to the problems in establishing a legitimate government and national forces. Bodies of Sunnis and Shiites were discovered in unmarked graves, and killings struck at both Sunni and Shiite clergy.

In addition to assassinations aimed at disrupting the judicial and political process, insurgents have carried out assassinations of religious leaders as part of their larger goal of using sectarian violence to provoke a civil war. There appeared to be an uptick in these assassinations in late summer and early fall 2005.