After that battle, control of the city was transferred to an Iraqi-run local security force, which began stockpiling weapons and building complex defenses.

Shortly afterward, on 31 March 2004, four American private military contractors from Blackwater – Wesley Batalona, Scott Helvenston, Jerry Zovko, and Michael Teague – were ambushed and killed in the city.

[26] Although tactical commanders in Iraq considered these deaths militarily insignificant, U.S. political leaders disapproved of a measured approach targeting the perpetrators and instead requested a larger assault into the city.

[27] A leak later revealed that the main factor behind this[clarification needed] wasn't the killings themselves, but the circulation of images of the event which served as a symbol of opposition to American forces in Iraq.

[17] The Fallujah Brigade, composed of local Iraqis under the command of a former Ba'athist officer named Muhammed Latif, took control of the city.

[29] Insurgent strength and control began to grow to such an extent that by 24 September 2004, a senior U.S. official told ABC News that catching Abu Musab al-Zarqawi, said to be in Fallujah, was now "the highest priority," and estimated his troops at 5,000 men, mostly non-Iraqis.

[30] However, the stated purpose of the military operation in Fallujah was to weaken the insurgency in preparation for the planned Iraqi elections in January 2005.

[31] Before beginning their attack, U.S. and Iraqi forces had established checkpoints around the city to prevent anyone from entering, and to intercept insurgents attempting to flee.

An estimated 2,000 insurgents were from the Army of Mohammed (made up of ex Fedayeen Saddam fighters), Ansar al-Sunna and various smaller Iraqi groups.

They blocked streets with Jersey barriers and even emplaced them within homes to create strong points behind which they could attack unsuspecting troops entering the building.

[41] Intelligence briefings given prior to battle reported that coalition forces would encounter Chechen, Filipino, Saudi, Libyan, and Syrian combatants, as well as native Iraqis.

[46] With Navy SEAL and Marine Recon Snipers providing reconnaissance and target marking on the city perimeter, ground operations began on the night of 7 November 2004.

2nd Infantry Division, Manchu, Charlie Co 1-9 Infantry Mechanized with 1st and 2nd platoons, (US Army) SEAL Sniper Task Elements from Naval Special Warfare Task Group Central and the U.S. Marine Corps Scout Platoons, captured Fallujah General Hospital, Blackwater Bridge, ING building, and villages opposite of the Euphrates River along Fallujah's western edge.

[47] These initial attacks, however, were a diversion intended to distract and confuse insurgents holding the city, preceding the all-out offensive.

The RCTs were augmented by three 7-man SEAL Sniper Teams from Naval Special Warfare Task Group-Central and one platoon from 1st Recon, who provided advance reconnaissance in the city, Joint Terminal Aircraft Control (JTAC) and unilateral overwatch throughout the operation.

The six battalions of U.S. and Iraqi forces, aided by Marine Corps Scout and Target Acquisition, SEAL Sniper, and JTAC elements pre-fire operations, moved into the city under the cover of darkness; and once aligned with the reconnaissance elements, began the assault in the early hours of 8 November 2004, preceded by an intense artillery barrage firing some 2500 155mm projectiles and air attack.

Shortly after nightfall on 9 November 2004, Marines had reportedly reached Phase Line Fran at Highway 10 in the center of the city.

While most of the fighting subsided by 13 November 2004, U.S. Marines and Special Operations Forces continued to face determined isolated resistance from insurgents hidden throughout the city.

By late January 2005, news reports indicated U.S. combat units were leaving the area, and were assisting the local population in returning to the now heavily damaged city.

[64] The 3rd Marine Air Wing (aviation assets only) expended 318 precision bombs, 391 rockets and missiles, and 93,000 machine gun and cannon rounds.

Reconstruction progressed slowly and mainly consisted of clearing rubble from heavily damaged areas and reestablishing basic utilities.

Tactics developed in what has been called the "Third Battle of Fallujah," when applied on a larger scale in Ramadi and the surrounding area, led to what became known as "the Great Sunni Awakening."

Al Qaeda-linked Sunni insurgents from the Islamic State in Iraq and the Levant subsequently took over Fallujah and parts of Ramadi in early 2014 and the city was reclaimed by the Iraqi Army and Special Operations Units in June 2016.

Included were graphic video and photos of severe and deep chemical burns that penetrated the flesh and bones of men, women, and children.

However, later the same day, US Department of Defense spokesman Lieutenant Colonel Barry Venable confirmed to the BBC that US forces had used white phosphorus as an incendiary weapon there.

"[86][87] On November 16, 2005, BBC News reported that an article published in the March–April 2005 issue of Field Artillery, a U.S. Army magazine, noted that white phosphorus had been used during the battle.

We used it for screening missions at two breeches and, later in the fight, as a potent psychological weapon against the insurgents in trench lines and spider holes where we could not get effects on them with HE [High Explosives].

They leveled thousands of buildings, illegally denied access to the Iraqi Red Crescent and, according to the UN's special rapporteur, used "hunger and deprivation of water as a weapon of war against the civilian population".

[94] A July 2009 paper by Buzby et al. reported a high level of cancer, birth defects and infant mortality, according to a house-to-house survey in Fallujah.

"[97] The results of a 2010 study at Fallujah General Hospital, published in 2012, concluded that, "the higher rates of congenital anomalies are believed to be caused by exposure to some genotoxic agent, possibly uranium.