Defense Secretary Robert Gates has endorsed a new five-year, $17 billion plan to increase the size of the Afghan army by about 50,000 troops.

The move follows a proposal from the Afghanistan government, and the price tag includes the costs for routine Afghan Army combat operations and upgrading the air corps, beginning in 2010, Pentagon press secretary Geoff Morrell said Friday.

He said it generally costs about $1 billion a year to increase forces by 10,000, and another $100,000 to sustain them.

Officials are currently looking at ways to finance it. Options 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. Currently there are about 65,000 soldiers in the Afghan Army, and that total is expected to hit the 80,000 goal next year, Morrell said.

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 34,000 U.S. troops in Afghanistan, the highest since the war began.

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 troop levels are reduced in Iraq they will be able to begin shifting combat forces to Afghanistan by early next year.

Late last week, the Pentagon ordered about 175 additional troops to Afghanistan, as part of an effort to beef up the fighting force by sending some smaller, specialized units there. The latest move included eight helicopter crews, largely from western Iraq.

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.

Internal discussions about expanding the U.S. command role were described in Associated Press interviews in April with several senior defense officials.

The move to an impending decision was first reported by The New York Times.