U.S. President Barack Obama is considering sending fewer troops than requested by his top commander in Afghanistan, according to reports. (Jim Young/Reuters)

U.S. President Barack Obama is considering sending large numbers of additional soldiers to Afghanistan next year but fewer than his war commander, Gen. Stanley McChrystal, prefers, U.S. officials say.

Under the pared-down option, McChrystal would be given fewer forces than the 40,000 additional troops he has asked for atop the current U.S. force of 68,000, officials told The Associated Press on Wednesday.

Senior White House officials stressed, however, that the president has not settled on any new troop numbers and continues to debate other strategic approaches to the eight-year-old Afghanistan war.

The officials say Obama has not yet firmly settled on the narrowed option or any other as his final choice for how to overhaul the war effort.

Two officials, speaking on condition of anonymity because Obama has not announced his decision, said the troop numbers under the narrowed scenario probably would be lower than McChrystal's preference, at least at the outset. The officials did not divulge exact numbers.

The stripped-down version of McChrystal's plan still would adopt the commander's overall goals for a counterinsurgency strategy aimed at turning the corner against the Taliban next spring.

But that pared-down approach would reflect a shift in thinking about what parts of the war mission are most important and the intense political domestic debate over Afghan policy.

Obama could face political fight

A majority of Americans either oppose the war or question whether it is worth continuing to wage, according to public opinion polls dating to when Obama shook up the war's management and began a lengthy reconsideration of U.S. objectives earlier this year.

Any expansion of the war will displease some congressional Democrats. If Obama does not meet McChrystal's request, Republicans are likely to accuse Obama of failing to give McChrystal all of what he needs.

A stripped-down approach would signal caution in widening a war that is going worse this year than last despite intense U.S. attention and an additional 21,000 U.S. forces on Obama's watch.

Fourteen Americans were killed Monday in Afghanistan in two helicopter crashes, and roadside bombings Tuesday left eight U.S. troops dead. October has been the worst month for U.S. fatalities since the U.S.-led invasion of Afghanistan began in October 2001.

Defence Secretary Robert Gates has pushed back hard against a faction of administration officials, led by Vice-President Joe Biden, who contend that much of the U.S. national security objective in Afghanistan could be accomplished by concentrating on strikes at al-Qaeda along the Pakistan border.

That approach would hunt terrorists with techniques such as missile-loaded pilotless drones, and could require little or no additional U.S. manpower.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, is on record supporting a troop increase. He has not quantified his preference, but he signed off on McChrystal's assessment of the worsening conditions in Afghanistan and the need for a change in approach and boost in manpower.

Gates has not given a public opinion on McChrystal's request but has pushed for the commander's overarching strategy during recent weeks of review by the White House, officials said.

McChrystal's recommendations got broad endorsement from NATO defence chiefs last week, with the suggestion that some nations will increase troops or other resources.