Civil war in Iraq In 2006 and 2007 , Iraq experienced a high level of sectarian violence . Some scholars and journalists state that the country was experiencing a civil war . Following the U . S . - launched 2003 invasion of Iraq , intercommunal violence between Iraqi Sunni and Shi ' a factions became prevalent . In February 2006 , the Sunni organization Al - Qaeda in Iraq bombed one of the holiest sites in Shi ' a Islam - the al - Askari Mosque in Samarra . This set off a wave of Shi ' a reprisals against Sunnis followed by Sunni counterattacks . The conflict escalated over the next several months until by 2007 , the National Intelligence Estimate described the situation as having elements of a civil war . In 2008 and 2009 , during the Sunni Awakening and the surge , violence declined dramatically . However , low - level strife continued to plague Iraq as late as 2013 ; see Iraqi insurgency ( Iraq War ) and Iraqi insurgency ( post - U . S . withdrawal ) . Two polls of Americans conducted in 2006 found that between 65 % to 85 % believed Iraq was in a civil war ; however , a similar poll of Iraqis conducted in 2007 found that 61 % did not believe that they were in a civil war . In October 2006 , the Office of the United Nations High Commissioner for Refugees ( UNHCR ) and the Iraqi government estimated that more than 370 , 000 Iraqis had been displaced since the 2006 bombing of the al - Askari Mosque , bringing the total number of Iraqi refugees to more than 1 . 6 million . By 2008 , the UNHCR raised the estimate of refugees to a total of about 4 . 7 million ( ~ 16 % of the population ) . The number of refugees estimated abroad was 2 million ( a number close to CIA projections ) and the number of internally displaced people was 2 . 7 million . The estimated number of orphans across Iraq has ranged from 400 , 000 ( according to the Baghdad Provincial Council ) , to five million ( according to Iraq ' s anti - corruption board ) . A UN report from 2008 placed the number of orphans at about 870 , 000 . The Red Cross stated in 2008 that Iraq ' s humanitarian situation was among the most critical in the world , with millions of Iraqis forced to rely on insufficient and poor - quality water sources . According to the Failed States Index , produced by Foreign Policy magazine and the Fund for Peace , Iraq was one of the world ' s top 5 unstable states from 2005 to 2008 . A poll of top U . S . foreign policy experts conducted in 2007 showed that over the next 10 years , just 3 % of experts believed the U . S . would be able to rebuild Iraq into a " beacon of democracy " and 58 % of experts believed that Sunni - Shiite tensions would dramatically increase in the Middle East . Ethno - sectarian composition . The population of Iraq can be divided into several main ideological or ethnic strands : " Religions " : The main two participants in the violence were the Arab Sunni and Arab Shia factions , but conflicts within a single group also occurred . The Kurds were caught between the two religious groups , but as they were an ethnicity as opposed to a religious movement , they were often at odds with the Arabs that were settled in Iraqi Kurdistan by Saddam ' s Arabization policy . Blurring this cohesion , though , were division of social , economic , political and geographic identities . Participants . A multitude of groups formed the Iraqi insurgency , which arose in a piecemeal fashion as a reaction to local events , notably the realisation of the U . S . military ’ s inability to control Iraq . Beginning in 2005 the insurgent forces coalesced around several main factions , including the Islamic Army in Iraq and Ansar al - Sunna . Religious justification was been used to support the political actions of these groups , as well as a marked adherence to Salafism , branding those against the jihad as non - believers . This approach played a role in the rise of sectarian violence . The U . S . military also believe that between 5 - 10 % of insurgent forces are non - Iraqi Arabs . Independent Shi ' ite militias identified themselves around sectarian ideology and possessed various levels of influence and power . Some militias were founded in exile and returned to Iraq only after the toppling of Saddam Hussein , such as the Badr Organization . Others were created since the state collapse , the largest and most uniform of which was the Mahdi Army established by Moqtada al - Sadr and believed to have around 50 , 000 fighters . Conflict and tactics . Non - military targets . Attacks on non - military and civilian targets began in earnest in August 2003 as an attempt to sow chaos and sectarian discord . Iraqi casualties increased over the next several years . Bomb and mortar attacks . Bomb attacks aimed at civilians usually targeted crowded places such as marketplaces and mosques in Shi ' ite cities and districts . The bombings , which were sometimes co - ordinated , often inflicted extreme casualties . For example , the 23 November 2006 Sadr City bombings killed at least 215 people and injured hundreds more in the Sadr City district of Baghdad , sparking reprisal attacks , and the 3 February 2007 Baghdad market bombing killed at least 135 and injured more than 300 . The co - ordinated 2 March 2004 Iraq Ashura bombings ( including car bomb s , suicide bomber s and mortar , grenade and rocket attacks ) killed at least 178 people and injured at least 500 . Suicide bombings . Since August 2003 , suicide car bombs were increasingly used as weapons by Sunni militants , primarily al - Qaeda extremists . The car bombs , known in the military as vehicle - borne improvised explosive device s ( VBIEDs ) , emerged as one of the militants ' most effective weapons , directed not only against civilian targets but also against Iraqi police stations and recruiting centers . These vehicle IEDs were often driven by the extremists from foreign Muslim countries with a history of militancy , such as Saudi Arabia , Algeria , Egypt , and Pakistan . Death squads . Death squad - style killings in Iraq took place in a variety of ways . Kidnapping , followed by often extreme torture ( such as drilling holes in peoples feet with drill s ) and execution - style killings , sometimes public ( in some cases , beheading s ) , emerged as another tactic . In some cases , tapes of the execution were distributed for propaganda purposes . The bodies were usually dumped on a roadside or in other places , several at a time . There were also several relatively large - scale massacres , like the Hay al Jihad massacre in which some 40 Sunnis were killed in a response to the car bombing which killed a dozen Shi ' ites . The death squads were often disgruntled Shi ' ites , including members of the security forces , who killed Sunnis to avenge the consequences of the insurgency against the Shi ' ite - dominated government . Attacks on places of worship . On February 22 , 2006 , a highly provocative explosion took place at the al - Askari Mosque in the Iraqi city of Samarra , one of the holiest sites in Shi ' a Islam , believed to have been caused by a bomb planted by al - Qaeda in Iraq . Although no injuries occurred in the blast , the mosque was severely damaged and the bombing resulted in violence over the following days . Over 100 dead bodies with bullet holes were found on the next day , and at least 165 people are thought to have been killed . In the aftermath of this attack the U . S . military calculated that the average homicide rate in Baghdad tripled from 11 to 33 deaths per day . Dozens of Iraqi mosques were aftwerwards attacked or taken over by the sectarian forces . For example , a Sunni mosque was burnt in the southern Iraqi town of Haswa on March 25 , 2007 , in the revenge for the destruction of a Shia mosque in the town the previous day . In several cases , Christian churches were also attacked by the extremists . Later , another al - Askari bombing took place in June 2007 . Iraq ' s Christian minority also became a target by Al Qaeda Sunnis because of conflicting theological ideas . Sectarian desertions . Some Iraqi service members deserted the military or the police and others refused to serve in hostile areas . For example , some members of one sect refused to serve in neighborhoods dominated by other sects . The ethnic Kurdish soldiers from northern Iraq , who were mostly Sunnis but not Arabs , were also reported to be deserting the army to avoid the civil strife in Baghdad . Timeline . For more information on events in a specific year , see the associated timeline page . Growth in refugee flight . By 2008 , the UNHCR raised the estimate of refugees to a total of about 4 . 7 million , with 2 million displaced internally and 2 . 7 million displaced externally . In April 2006 the Ministry of Displacement and Migration estimated that " nearly 70 , 000 displaced Iraqis , especially from the capital , are living in deteriorating conditions , ” due to ongoing sectarian violence . Roughly 40 % of Iraq ' s middle class is believed to have fled , the U . N . said . Most were fleeing systematic persecution and had no desire to return . Refugees were mired in poverty as they were generally barred from working in their host countries . A May 25 , 2007 article noted that in the past seven months only 69 people from Iraq had been granted refugee status in the United States . Use of " Civil War " label . The use of the term " civil war " has been controversial , with a number of commentators preferring the term " civil conflict " . A poll of over 5 , 000 Iraqi nationals found that 27 % of polled Iraqi residents agreed that Iraq was in a civil war , while 61 % thought Iraq was not . Two similar polls of Americans conducted in 2006 found that between 65 % to 85 % believed Iraq was in a civil war . In the United States , the term has been politicized . Deputy leader of the United States Senate , Dick Durbin , referred to " this civil war in Iraq " in a criticism of George W . Bush ' s January 10 , 2007 , President ' s Address to the Nation . Edward Wong on November 26 , 2006 paraphrased a report from a group of American professors at Stanford University that the insurgency in Iraq amounted to the classic definition of a civil war . An unclassified summary of the 90 - page January 2007 National Intelligence Estimate , titled " Prospects for Iraq ' s Stability : A Challenging Road Ahead " , states the following regarding the use of the term " civil war " : Retired United States Army General Barry McCaffrey issued a report on March 26 , 2007 , after a trip and analysis of the situation in Iraq . The report labeled the situation a " low - grade civil war . " In page 3 of the report , he writes that : See also . Events : General :