More troops and a new strategy for using them are emerging as critical components to the 8-year-old effort by U.S. and NATO forces to defeat the Taliban and secure Afghanistan.

Defense Secretary Robert Gates, acknowledging bright spots but also "gloom and doom" in a new assessment of the war, said Monday the Obama administration would look closely at requests for resources.

Asking for more troops is not part of the classified assessment delivered by Gen. Stanley McChrystal, the top commander in Afghanistan, according to officials. However, he is expected to ask for more troops in a separate request in a few weeks, two NATO officials told The Associated Press on condition of anonymity. They were not authorized to speak publicly on the matter.

McChrystal''s assessment is expected to offer a blunt appraisal of the Taliban''s increasing tactical prowess and diminishing popular support in Afghanistan for both the foreign-led war effort and the fragile, corruption-riddled central government.