BAGHDAD — The US military is holding steady in its aim to reduce troop numbers in Iraq to 50,000 by Aug 31, when the 7-1/2 year US combat mission launched by former President George W. Bush comes to an official close.

The last US brigade officially classed as a combat unit formally handed over responsibilities to its Iraqi counterparts on Aug 7, but US troops have been steadily flowing out of the country on transport aircraft and by road for a year.

US media said on Wednesday the last US combat troops had left Iraq, but US officials clarified there were still 56,000 US soldiers in Iraq, so the reduction to 50,000 non-combat troops by Sept 1 promised by President Barack Obama still has a some way to go.

There will actually be little change on the ground in the US military mission in Iraq come Sept 1 as most US military units began switching their focus to training and assisting Iraqi troops and police more than a year ago when they pulled out of Iraqi urban centers on June 30, 2009.

Much of the US war material and many of the soldiers departing Iraq are being redeployed to Afghanistan, where NATO forces are fighting a resurgent Taliban.

The end of the US combat mission in Iraq will mark a milestone in the war that began in 2003 with the invasion to topple Saddam Hussein, whose long rule was marked by an eight-year war with Iran, the invasion of Kuwait, economic decline and diplomatic isolation.

More than 4,400 US soldiers have been killed since the invasion and thousands have been injured. The total number of Iraqis who died as a result of the invasion and occupation that followed is not clear, although some estimates run as high as one million.

More than two million others, however, are known to have been displaced inside Iraq, or have become refugees overseas.