The Second Battle of Fallujah, initially codenamed Operation Phantom Fury, Operation al-Fajr (, ) was an American-led offensive of the Iraq War that began on 7 November 2004 and lasted about six weeks.

A joint military effort of the United States, the Iraqi Interim Government, and the United Kingdom, the battle was the war's first major engagement fought solely against the Iraqi insurgency, not the military forces of the Ba'athist Iraq government.

Operation Phantom Fury took place seven months after the First Battle of Fallujah, an attempt to capture or kill insurgent elements involved in the 2004 Fallujah ambush that killed four employees of the private military contractor Blackwater. After that battle, control of the city was transferred to an Iraqi-run local security force, which began stockpiling weapons and building complex defenses.Ricks, (2007) pp. 343–346.

Led by the U.S. Marine Corps and U.S. Army, the Second Battle of Fallujah was later described as "some of the heaviest urban combat Marines and Soldiers have been involved in since Huế City in Vietnam in 1968" and as the toughest battle the U.S. military has been in since the end of the Vietnam War.Ricks, Thomas E. (2007). Fiasco: The American Military Adventure in Iraq, 2003–2005. Penguin. p. 399. . It was the single bloodiest and fiercest battle of the entire conflict, including for American troops. It was also noted for the use of white phosphorus by U.S. forces.US admits using white phosphorus in Falluja, The Guardian

Background In February 2004, control of Fallujah and the surrounding area in the Al Anbar Governorate was transferred from the United States 82nd Airborne Division to the 1st Marine Division. 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. Images of their mutilated bodies were broadcast around the world. Journalist Jeremy Scahill later called this incident the Mogadishu moment of the Iraq War (referencing the Battle of Mogadishu, also known as the "Black Hawk Down" incident). 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. A leak later revealed that the main factor behind this incident 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.

Within days, U.S. Marine Corps forces launched Operation Vigilant Resolve (5 April 2004) to take back control of the city from insurgent forces. On 28 April 2004, Operation Vigilant Resolve ended with an agreement where the local population was ordered to keep the insurgents out of the city. The Fallujah Brigade, composed of local Iraqis under the command of a former Ba'athist officer named Muhammed Latif, took control of the city.

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-Iraqi jihadists. 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.

Preparations Coalition forces

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. In addition, overhead imagery was used to prepare maps of the city for use by the attackers. American units were augmented by Iraqi interpreters to assist them in the planned fight. After weeks of withstanding air strikes and artillery bombardment, the militants in the city appeared to be vulnerable to direct attack.

U.S., Iraqi and British forces totaled about 13,500. The U.S. had gathered some 6,500 Marines and 1,500 Army soldiers that would take part in the assault with about 2,500 Navy personnel in operational and support roles. U.S. troops were grouped in two Regimental Combat Teams: Regimental Combat Team 1 comprised 3rd Battalion/1st Marines, 3rd Battalion/5th Marines, and U.S. Army 2d Battalion/7th Cavalry. Regimental Combat Team 7 comprised the 1st Battalion/8th Marines, 1st Battalion/3rd Marines, U.S. Army 2d Battalion/2d Infantry, 2d Battalion/12th Cavalry.Lowry, Richard S. (2010). New Dawn: The Battles for Fallujah. Savas Beatie. pp. 269–279. . About 2,000 Iraqi troops assisted with the assault. All were supported by Marine fixed and rotary-winged aircraft, Navy and Air Force fixed-wing aircraft; and USSOCOM Sniper Elements.

The 850-strong 1st Battalion of the Black Watch was ordered to help U.S. and Iraqi forces with the encirclement of Fallujah. As part of Task Force Black, D Squadron of the British SAS prepared to take part in the operation, but British political nervousness about the possible scale of casualties stopped any direct UK involvement in the ground battle.Urban, Mark, Task Force Black: The Explosive True Story of the Secret Special Forces War in Iraq , St. Martin's Griffin, 2012 , p.65

Insurgent forces In April, Fallujah was occupied by about 500 "hardcore" and 1,000+ "part time" insurgents. By November, it was estimated that the numbers had doubled. Another estimate put the number of insurgents at 3,000; however, a number of insurgent leaders escaped before the attack.

Fallujah was occupied by virtually every insurgent group in Iraq: al-Qaeda in Iraq (AQI), Islamic Army of Iraq (IAI), Ansar al-Sunna, Army of Mohammed (AOM), the Army of the Mujahedeen and the Secret Islamic Army of Iraq. Three groups, (AQI, IAI and the National Islamic Army (1920 Revolution Brigade)) had their nationwide headquarters in Fallujah. 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.Nance, Malcolm W., The Terrorists of Iraq: Inside the Strategy and Tactics of the Iraq Insurgency 2003–2014, CRC Press, 2014

Unlike what most cities in Iraq saw, the Battle of Fallujah did not have internal disputes between insurgents. The fighters consisted of both Sunnis and Shi'as; Soldiers of the Mahdi army fought alongside Sunni and Ba'athist groups against the United States. The Iraqi insurgents and foreign Mujahideen present in the city prepared fortified defenses in advance of the anticipated attack.Lowry, Richard S. (2010). New Dawn: The Battles for Fallujah. Savas Beatie. p. 20. . They dug tunnels, trenches, prepared spider holes, and built and hid a wide variety of IEDs. In some locations, they filled the interiors of darkened homes with large numbers of propane bottles, large drums of gasoline, and ordinance, all wired to a remote trigger that could be set off by an insurgent when troops entered the building. 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. Insurgents were equipped with a variety of advanced small arms, and had captured a variety of U.S. armament, including M14s, M16s, body armor, uniforms and helmets.

They booby-trapped buildings and vehicles, including wiring doors and windows to grenades and other ordnance. Anticipating U.S. tactics to seize the roofs of high buildings, they bricked up stairwells to the roofs of many buildings, creating paths into prepared fields of fire which they hoped the troops would enter.

Intelligence briefings given prior to battle reported that coalition forces would encounter Chechen, Filipino, Egyptian, Saudi, Jordanian, and Syrian combatants, as well as native Iraqis.Bellavia, David & Bruning, John. House to House: An Epic Memoir of War Free Press. (2007) .

Civilian presence Most of Fallujah's civilian population fled the city before the battle, which greatly reduced the potential for noncombatant casualties. U.S. military officials estimated that 70–90% of the 300,000 civilians in the city fled before the attack, leaving 30,000 to 90,000 civilians still in the city. The military used leaflets and broadcasts to encourage civilians to leave the city before the assault. However, multiple news agencies reported that military-aged males were prevented from leaving or entering the city by the U.S. military. Additionally, not all civilians had the means to leave Fallujah before the battle. Jane Arraf, who was embedded with U.S. troops, said that some families wrote "We are family" on the doors of their homes, hoping the Marines would not attack during the battle.

Battle

Diversion With Navy SEAL and Force Recon Scout Snipers providing reconnaissance and target marking on the city perimeter, ground operations began on the night of 7 November 2004. Attacking from the west and south, the Iraqi 36th Commando Battalion with their U.S. Army Special Forces advisers, 1st and 2nd Platoon Charlie Company, Manchu 1st Battalion 9th Infantry Regiment Mechanized, 2nd Brigade Combat Team, 2nd Infantry Division (U.S. Army) served as the main effort on the peninsula and supported by 3rd Platoon Alpha Company 2/72nd Tank Battalion (U.S. Army), and 3rd Light Armored Reconnaissance Battalion, reinforced by Bravo Company from the Marine Corps Reserve's 1st Battalion, 23rd Regiment, and supported by Combat Service Support Company 122.

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.Wise p. 75 Marines from 1/3 fired 81mm mortars in an operation in south Fallujah. The same unit then moved to the western approaches to the city and secured the Jurf Kas Sukr Bridge. These initial attacks, however, were a diversion intended to distract and confuse insurgents holding the city, preceding the all-out offensive. Two Marines died in the initial attacks when their bulldozer fell into the Euphrates River. 42 insurgents were killed along the Fallujah riverside.

Main attack