The new plan will cost well over $10 billion. Pentagon press secretary Geoff Morrell said Thursday officials are currently looking at ways to finance it. Options would include seeking money from NATO allies.
Morrell said the proposal would increase the size of the Afghan army from a planned 80,000 troops to roughly 122,000, plus 13,000 in support staff.
In addition, Gates is poised to approve a plan that would give Army Gen. David McKiernan broader control over U.S. forces in Afghanistan. Currently, McKiernan commands the NATO-led coalition in Afghanistan, which includes about 15,000 U.S. forces. Under the new proposal, McKiernan also would control the additional U.S. forces in Afghanistan who are training the Afghan army and police. There are about 33,000 U.S. troops in Afghanistan, the highest since the war began.
All told, the five-year plan could cost about $20 billion, according to The New York Times, which first reported the proposal on it Web site late Thursday.
Attacks from Taliban militants have spiked in recent months in Afghanistan, and commanders there have said repeatedly that they need additional U.S. forces. Commanders have asked for three additional combat brigades, and military officials hope that as troops levels are reduced in Iraq they will be able to shift forces to Afghanistan by early next year.
May, June and July have been the deadliest three months for American forces in Afghanistan, pushing the U.S. death toll there to at least 500.
The Pentagon long has been considering military commanders' suggestions to better coordinate the mission in Afghanistan.
"The U.S. is looking to streamline the command and control by making McKiernan essentially in charge of all U.S. forces in Afghanistan so that one person can deploy them in support of the overall mission," Morrell said.
The plan, which does not yet have final approval, would leave the smaller number of U.S. forces who are battling the Taliban and overseeing detainees under the control of U.S. Central Command. Currently, U.S. Central Command also directs the training forces.
Morrell said the proposal would not blend the NATO and training missions together.
He added that this "imminent" decision has come after close consultation with leaders of the NATO allies.
The move to add to McKiernan's authority is designed to extend U.S. control of forces into the country's volatile south, an idea partly linked to an expectation of a fresh infusion of U.S. combat troops in the south next year.
Taliban resistance has stiffened in the south since NATO took command there in mid-2006, and some in the Bush administration believe the fight against the Taliban could be strengthened if the U.S., whose span of control is now limited to eastern Afghanistan, also was in charge in part or all of the south.
Internal discussions about expanding the U.S. command role were described in Associated Press interviews in April with several senior defense officials.
Giving the U.S. more control in the south would address one problem cited by U.S. officials: the NATO allies' practice of rotating commanders every nine months - and their fighting units every six months, in some cases. In the U.S. view, nine-month commands are too short to maximize effectiveness.
U.S. combat tours in Afghanistan and Iraq were to shrink to 12 months starting Aug. 1.
Changing the command structure to give a U.S. general more control in the south would, in effect, mark a partial "re-Americanization" of the combat mission. That could be politically controversial, given U.S. interests in maintaining close ties with NATO in fighting terrorism.