What Is 2006-2007 civil war in Iraq

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Last updated: April 15, 2026

Quick Answer: The 2006–2007 civil war in Iraq was a period of intense sectarian violence between Sunni and Shia Muslims, peaking after the February 2006 bombing of the Al-Askari Mosque. An estimated 15,000–34,000 civilians died in 2006 alone, with violence spreading across Baghdad and central Iraq.

Key Facts

The civil war phase began in February 2006 after the bombing of the Al-Askari Mosque in Samarra
Over 34,000 civilians were killed in Iraq in 2007, the deadliest year of the conflict
Baghdad became the epicenter of sectarian death squads and ethnic cleansing
The U.S. launched a 'surge' of 30,000 additional troops in 2007 to stabilize the country
Shia-dominated government forces and Sunni insurgent groups committed widespread atrocities

Overview

The 2006–2007 phase of the Iraq conflict escalated into a full-scale sectarian civil war following years of instability after the 2003 U.S.-led invasion. Triggered by the February 22, 2006, bombing of the Al-Askari Mosque in Samarra—a sacred Shia site—the violence rapidly spiraled into widespread retaliatory attacks between Sunni and Shia communities.

This period marked the deadliest phase of the Iraq War, characterized by ethnic cleansing, death squad operations, and near-total breakdown of state security. The central government struggled to maintain control as sectarian militias, including the Mahdi Army and Sunni insurgent factions, operated with significant autonomy.

February 2006 bombing: The destruction of the Al-Askari Mosque by al-Qaeda in Iraq ignited nationwide Shia outrage and marked the official start of intense civil conflict.
Civilian casualties: The Iraq Body Count project documented between 15,000 and 34,000 civilian deaths in 2006 and over 34,000 in 2007, the highest annual toll.
Baghdad's sectarian divide: Entire neighborhoods like Adhamiya (Sunni) and Sadr City (Shia) became militarized zones, with over 150,000 people displaced due to ethnic cleansing by militias.
U.S. military presence: At its peak in 2007, the U.S. had 160,000 troops in Iraq, struggling to contain violence despite controlling key infrastructure.
Militia influence: The Shia Mahdi Army, led by Muqtada al-Sadr, and Sunni groups like al-Qaeda in Iraq carried out systematic killings and kidnappings.

Key Actors and Militias

Multiple armed factions shaped the trajectory of the civil war, each with distinct ideologies, leadership, and foreign backing. Control over territory and population centers shifted frequently, often along sectarian lines.

Al-Qaeda in Iraq (AQI): Led by Abu Musab al-Zarqawi until his death in June 2006, AQI targeted Shia civilians and U.S. forces, aiming to provoke sectarian war.
Mahdi Army: A Shia militia loyal to Muqtada al-Sadr, active in Baghdad and southern Iraq, responsible for death squads and attacks on Sunni neighborhoods.
Badr Organization: The military wing of the Supreme Council for the Islamic Revolution in Iraq, trained in Iran and integrated into Iraqi security forces by 2006.
Sunni insurgent coalitions: Included former Ba'athists and tribal fighters, later forming the Sunni Awakening councils to oppose AQI.
Coalition forces: U.S. and British troops attempted to stabilize regions but were often seen as partisan, especially after supporting Shia-led governments.
Iranian involvement: Provided weapons, training, and funding to Shia militias, exacerbating sectarian tensions and undermining Iraqi sovereignty.

Comparison at a Glance

Below is a comparison of key indicators during the peak civil war years versus the years immediately before and after:

Metric	2005	2006	2007	2008
Civilian deaths (approx.)	10,000	15,000–34,000	Over 34,000	Approx. 8,000
U.S. troop levels	138,000	144,000	160,000 (surge)	140,000
Displaced persons (IDPs)	1.6 million	2.2 million	2.7 million	2.8 million
Major incidents/month	1,200	1,800	Over 2,000	1,100
Shia militia control in Baghdad	Limited	Expanding	Widespread	Reduced due to surge

The data shows a sharp increase in violence from 2005 to 2007, followed by a decline in 2008 due to the U.S. troop surge and the Sunni Awakening movement. Despite improvements, displacement continued to rise as trust between communities eroded.

Why It Matters

The 2006–2007 civil war reshaped Iraq’s political and social landscape, leaving long-term consequences for regional stability and U.S. foreign policy. Understanding this period is essential for analyzing modern Middle Eastern conflicts and the consequences of military intervention.

Legacy of sectarianism: Deep mistrust between Sunni and Shia communities persists, undermining national unity and fueling future insurgencies like ISIS.
Rise of ISIS: The collapse of Sunni political representation and abuses by Shia militias created fertile ground for ISIS’s 2014 expansion.
U.S. policy shift: The 2007 surge, adding 30,000 U.S. troops, temporarily reduced violence but delayed long-term political solutions.
Humanitarian crisis: By 2008, over 2.7 million Iraqis were internally displaced, with hundreds of thousands fleeing abroad.
Militia integration: Many Shia fighters were absorbed into official security forces, blurring lines between state and militia violence.
Regional influence: Iran’s support for Shia groups increased its strategic foothold in Iraq, altering Middle East power dynamics.

The 2006–2007 civil war was not just a spike in violence but a transformation of Iraq into a fragmented, sectarian state. Its effects continue to influence governance, security, and intercommunal relations today.