The alliance said on Monday it would end its mission after talks with Iraqi officials to extend the programme failed, due to disagreements over legal framework covering NATO forces in Iraq.

"We respect the decisions of a sovereign Iraq and salute the fact that Iraqi is fully responsible for directing its own path," NATO training mission commander Lieutenant General Robert Caslen said at the closing ceremony.

The decision followed US President Barack Obama's announcement in October that US troops would go home at year-end after talks to keep thousands in Iraq as trainers fell apart over Washington's demand for legal immunity for troops.

American forces signed over their last military base to Iraqi officials on Friday following a formal ceremony to end nearly nine years of war in Iraq.

NATO started its training mission in Iraq in 2004, although unlike in Afghanistan, its Iraq operation has been small and largely under the radar.

The alliance has provided expertise in areas like logistics and policing for Iraqi security forces, with around 100 troops training more than 5,000 military and 10,000 police in Iraq.