Analysis: Combat teams requested are capable of autonomous operations, writes Tom Clonan
Lieut Gen John Abizaid, Centcom's most senior commander in the Middle East, has called for troop reinforcements in an effort to restore order in Iraq.
When one looks more closely at this request, US intentions in Iraq become starkly apparent. Centcom has specifically called for two brigade combat teams to be deployed to Iraq.
Also known as "Stryker" brigades, these units - consisting of approximately 5,000 soldiers - are specifically configured for high-tempo combat operations.
These units are designed to be deployed from their bases in the US to combat zones anywhere in the world within 96 hours of mobilisation. Once on the ground, such formations are entirely independent and capable of autonomous and sustained combat operations with their own air, artillery and armoured support.
Brigade combat teams such as these, including the 3rd Brigade of the US 2nd Infantry Division recently deployed to Mosul, are specifically trained for combat operations in "complex terrain", a US military euphemism for urban warfare.
As such they are armed and equipped for "full spectrum combat operations" in the urban environment. These are precisely the type of combat operations seen recently in operation Vigilant Resolve in Falluja.
With their offensive in Falluja temporarily halted as negotiations with Sunni rebels continue, US commanders in Iraq are organising their troops for similar operations around Najaf and Karbala as part of operation Resolute Sword.
The casualty figures for Falluja suggest that upwards of 650 Iraqi civilians, including women and children, were killed in operation Vigilant Resolve, along with more than 1,200 wounded. Up to 70 US troops are reported to have been killed during the same period.
This "exchange ratio" of approximately one US soldier killed in action for every 10 Iraqis killed in-theatre is similar to that experienced by the British army in Kerbala and Najaf in 1920.
At that time, the British military lost 700 troops and killed approximately 7,000 Iraqi civilians as they sought to pacify Shia militants opposed to their occupation.
Based on such precedents, Centcom, the Coalition Provisional Authority and the Iraqi Governing Council can be in no doubt as to the likely outcome of a US or British military offensive in Kerbala and Najaf designed to kill or capture Moqtada al-Sadr and his Mahdi army.
Yesterday's arrest and sudden re-release of an al-Sadr aide, Sheikh Hazen al-Aaraji, by US troops may be evidence of efforts by the US-led coalition to negotiate a peaceful resolution to the Shia crisis in central Iraq.
If such negotiations fail, statements yesterday by Centcom's Brig Gen Mark Kimmitt confirm that the US military fully intend to use whatever military force is necessary to "wipe out" Shia violence and to either detain or kill al-Sadr and the Mahdi army leadership.
Gen Kimmitt also stated that such military operations were in the "preparatory" phase.
If such operations are imminent and if the mahdi army stands and fights in Najaf and Kerbala, casualties are likely to exceed those experienced in Falluja. In operation Vigilant Resolve, US marines of the 1st Marine Expeditionary Force have thus far only managed to penetrate and occupy around one quarter of downtown Falluja.
Approximately 60,000 men, women and children - roughly one-quarter of the total of Falluja's population of 250,000 - have been displaced by these operations.
Similar simultaneous operations in Najaf and Kerbala would see US troops seek to pacify a population concentration of over half-a-million Shia Muslims.
As the current crisis coincides with rotation dates for US and British troops, Centcom has at its disposal several thousand extra troops for offensive operations in central and southern Iraq. US military units including the 2nd Infantry Division, the 1st Marine Expeditionary Force and the 1st Cavalry Division have recently arrived in-country to relieve the 101st Airborne, the 82nd Airborne and the 1st Armoured Division.
At the same time, the British 1st Mechanised Brigade - with 5,000 troops - has just arrived in Basra to replace the 20th Armoured Brigade. As Centcom extends by four months the tours of duty of US combat troops due to rotate home and as Gen Abizaid calls for further reinforcements, the stage therefore seems set for a full-scale military confrontation within Iraq.
Unlike the air war and fast-moving ground campaign that characterised the advance on Baghdad this time last year, the current phase of the war in Iraq has the potential to escalate into a much bloodier and costlier affair for Centcom.
Dr Tom Clonan is a retired Army officer. He currently lectures in the School of Media at DIT.