Upon completion of the initial conflict the coalition troops began counterinsurgency, humanitarian, security, and various other types of operations to stabilize the country.
The southern and central portions of Iraq began to erupt in urban guerilla combat as coalition forces attempted to keep control and prepared for a counteroffensive.
In response to insurgent attacks, coalition forces focused on hunting down the remaining leaders of the former regime, culminating in the shooting deaths of Saddam's two sons in July.
The insurgency, the developing the New Iraqi Army, disorganized police and security forces, as well as a lack of revenue have hampered efforts to assert control.
In addition, former Baathist elements and militant Shia groups have engaged in sabotage, terrorism, open rebellion, and establishing their own security zones in all or part of a dozen cities.
Sectarian violence expanded to a new level of intensity following the al-Askari Mosque bombing in the Iraqi city of Samarra, on 22 February 2006.
As of 20 October the U.S military announced that Operation Together Forward had failed to stem the tide of violence in Baghdad, and Shiite militants under al-Sadr seized several southern Iraq cities.
Suspected Sunni-Arab militants used five suicide car bombs and two mortar rounds on the capital's Shiite Sadr City slum to kill at least 215 people and wound 257.
Shiite mortar teams quickly retaliated, firing 10 shells at Sunni Islam's most important shrine in Baghdad, badly damaging the Abu Hanifa mosque and killing one person.
On 10 January 2007, President Bush announced changes in the administration's political and military strategy in the Iraq War during a television speech broadcast.
In the address Bush stated "America will change our strategy to help the Iraqis carry out their campaign to put down sectarian violence and bring security to the people of Baghdad.