WASHINGTON - Facing a war-weary public, President Barack Obama is expected to call for a major withdrawal of American troops from Afghanistan Wednesday night, with roughly 10,000 coming home to the U.S. in less than a year.

The phased drawdown is likely to start with 5,000 troops recalled this summer and an additional 5,000 by winter or spring 2012, according to a senior U.S. defense official. Obama is also weighing a timetable for bringing home the 20,000 other troops he ordered to Afghanistan as part of his December 2009 decision to send reinforcements to reverse the Taliban's battlefield momentum.

The withdrawals would put the U.S. on a path toward giving Afghans control of their security by 2014 and ultimately shifting the U.S. military from a combat role to a mission focused on training and supporting Afghan forces.

Obama is to address the nation from the White House at 5 p.m. PDT tonight.

The president reached his decision a week after receiving a range of options from Gen. David Petraeus, the top U.S. and NATO commander in Afghanistan. Obama informed his senior national security advisers, including outgoing Defense Secretary Robert Gates and Secretary of State Hillary Rodham Clinton, of his plans during a White House meeting on Tuesday.

"The president is commander-in-chief," said spokesman Jay Carney. "He is in charge of this process, and he makes the decision."

The Obama administration has said its goal in continuing the Afghan war, now in its 10th year, is to blunt the Taliban insurgency and dismantle and defeat al-Qaida, the terror network that used Afghanistan as a training ground for the Sept. 11, 2001, attacks. As of Tuesday, at least 1,522 members of the U.S. military had died in Afghanistan as a result of the U.S. invasion of Afghanistan in late 2001, according to an Associated Press count.

Roughly 100,000 U.S. troops are in the country, three times as many as when Obama took office. Even by drawing down the 30,000 surge forces, there will still be great uncertainty about how long the remaining 70,000 troops would stay there, although the U.S. and its allies have set Dec. 31, 2014, as a target date for ending the combat mission in Afghanistan.

A reduction this year totaling 10,000 troops would be the rough equivalent of two brigades, which are the main building blocks of an Army division. It's not clear whether Obama's decision would require the Pentagon to pull out two full brigades or, instead, a collection of smaller combat and support units with an equivalent number of troops.

If Obama were to leave the bulk of the 30,000 surge contingent in Afghanistan through 2012, he would be giving the military another fighting season to further damage Taliban forces before a larger withdrawal got started.