Discuss as:

U.S. brigades out of Iraq, but not necessarily out of combat

As of this morning, there are about 56,000 American forces in Iraq. That number will be drawn down to about 50,000 by Aug. 31. As of last night, all American combat brigades are out of Iraq. About 6,000 combat forces, disparate elements of combat brigades remain in Iraq temporarily, but are not currently organized to conduct combat operations.

When combat operations officially end Aug 31, that does not mean that some of the 50,000 American forces that remain in Iraq will never see combat. Senior military official tell NBC News that the so-called advise and assist brigades that do not have a formal combat mission will, however, be combat capable. Some of those forces that will be embedded with Iraqi forces could indeed be drawn into combat.

About 4,500 American Special Operations forces will also continue to conduct counter-terrorism operations, hunting down and capturing or killing al Qadea members. While these operations are not considered formal combat mission, they often do result in combat tactics. Then there's the deadline to withdraw all American forces from Iraq by the end of 2011. The chief of the Iraqi military warned last week that Iraqi forces won't be fully capable of providing security for all of Iraq until 2020.

While senior military officials scoff at that timeline, some do acknowledge that, at this point, it appears the withdrawal agreement with the Iraqis may have to be renegotiated next year to permit some smaller numbers of American forces to remain in Iraq -- not in a formal role -- but to continue to work with Iraq forces.