From flyers warning troops the post office will shut soon to disused housing units waiting to be dispatched to their new destination, the signs are everywhere: US forces are packing up to leave Iraq more than eight years after they first arrived. The scale of the operation is unprecedented in the army\'s history -- preparing to transfer dozens of bases to the Iraqis, and handing over, disposing of or shipping out thousands of vehicles, generators, air conditioners and other materiel. Under the terms of a bilateral security pact with Iraq, the 47,000 US soldiers currently in the country must leave by the end of the year. \"Every time you pack up your place, (you think) where did this stuff come from?\" said Colonel Steve Cook, the top logistics officer for American forces in north Iraq, likening the process to moving house. \"It seems to be a lot more than you bargained for,\" he said in an interview at Contingency Operating Base Speicher on the outskirts of Tikrit, 160 kilometres (100 miles) north of Baghdad. Cook and other senior officers who arrived at COB Speicher, the US northern headquarters, toward the end of 2010, estimated that the majority of their task of moving soldiers, contractors and equipment out of Iraq had yet to be done. From the end of last year, around $30 million worth of non-military items on US bases in the north, such as generators and air conditioners, have been given to Iraq at no cost, under a programme authorised by the US Congress. Cook, 44, estimated that the monetary value of the items handed over would at least double by the end of the year as more is transferred. Overall, 105,000 such items have been transferred, having been deemed too expensive to ship back either to the United States or to other American military operations, such as in Afghanistan. And of the 4,500 military vehicles such as trucks and Humvees that the US held in October 2010 in the north, 2,800 have yet to be shipped out. Sixteen bases in the north have been handed over to Iraq, but 23 remain. \"The level of planning for the size of USD (US Division) North, with all the people and all the equipment, including contractors; how you synchronise all that to get everything out in an orderly fashion, there\'s no real \'how to\' book,\" Cook said. From August 1, US forces in the north will shift focus from training their Iraqi counterparts to the heavy logistical task of pulling out. \"The priority when we got here and really up until just recently was training the Iraqi security forces,\" said Brigadier General Jim Pasquarette, the senior officer responsible for carrying out the withdrawal in the north. \"Here soon, though... we will transition to where the main effort will be transitioning and the supporting effort will be training the Iraqi security forces.\" Pasquarette, 50, said his team was also putting together recommendations for their counterparts in Afghanistan, where the US military is withdrawing 33,000 of its 100,000 soldiers by September 2012. \"I think we\'re ploughing new ground for the army here in Iraq right now,\" Pasquarette said. \"We haven\'t really done this on this scale before.\" Though plans for a limited US military training mission to stay in Iraq beyond the year-end deadline are gaining traction, according to Foreign Minister Hoshyar Zebari, no concrete moves have yet been made toward a longer-term American presence. The complexity of the withdrawal is evident at COB Speicher, which at its peak was the largest American base in north Iraq -- with 20,000 soldiers and contractors as recently as last summer on an area covering 41.5 square kilometres (16 square miles). Now around 7,000 remain, according to Lieutenant Colonel Matthew Tedesco, who is in charge of the drawdown of the base, and turns 42 this month. Around 1,500 containerised housing units, each enough to house one or two people, have been either handed over to Iraqi authorities, sold for scrap or moved elsewhere. Half a dozen sit in one corner of the base with the letters BOR spray-painted on their doors, indicating they are bound for the nearby Baiji Oil Refinery. Another 1,000 tents, which typically hold between eight and 10 people, have also been taken down, and many of the facilities on the base designed to boost morale are also slowly being withdrawn. \"Some of the nice stuff to have is going away,\" Tedesco said, noting that the base\'s Burger King would soon close, as would the Green Bean cafe and commercially provided Internet connections for the soldiers\' private use. Flyers posted on bulletin boards across the base also warn soldiers that postal services will soon end, and those who require prescription medication to be sent to them must plan ahead. By the end of July, around a fifth of Speicher will have been handed over to Iraqi authorities, who have begun using it as an air force training college, the same role it played before the 2003 US-led invasion that ousted dictator Saddam Hussein. The entire base will be transferred in the early autumn, with Tedesco and other officers declining to give specifics on the date. Similar projects are ongoing at bases across the north and the rest of Iraq, with equipment due to leave being sent to Kuwait for shipment overseas. \"Only so much can get down through the pipe at a time, and it\'s not just us in the north moving,\" Pasquarette noted of the complexity of the task, with dozens of bases in central and south Iraq also being handed over. Cook added: \"Being here for eight years, you accumulate a lot of stuff.\" \"It sounds daunting, but you eat that elephant one bite at a time.