Fox News has learned that President Obama will announce Wednesday evening that he will withdraw 10,000 troops from Afghanistan by the end of this year.

The president is scheduled to address the nation at 8pm, Eastern time, from the White House to lay out the details.

Sources outside the White House also say that the rest of the 30,000 surge troops, approximately 23,000, will be removed by the "end of summer" 2012.

It is expected, say these sources, that by September 1, 2012, all of the U.S. surge troops that President Obama sent to Afghanistan to try to regain momentum there will be back home.

The president has long said he would wind down operations in Afghanistan as quickly as the situation allowed, but that the pace and scope of that withdrawal would be conditions-based. A senior administration official tells Fox that in making his decision the president focused on key areas. "As the President deliberated on the drawdown, progress made on the core goal against Al Qaeda and the objectives outlined in the paragraph below were the key factors," the official said, referring to the president's 2009 speech at West Point in which he announced his plan for the surge forces.

The plan then, as described by Mr. Obama, was this: "Our overarching goal remains the same: to disrupt, dismantle, and defeat al Qaeda in Afghanistan and Pakistan, and to prevent its capacity to threaten America and our allies in the future. To meet that goal, we will pursue the following objectives within Afghanistan. We must deny al Qaeda a safe haven. We must reverse the Taliban's momentum and deny it the ability to overthrow the government. And we must strengthen the capacity of Afghanistan's security forces and government, so that they can take lead responsibility for Afghanistan's future."

Watch Fox News Channel for all of the latest developments and stay tuned to FNC or your broadcast Fox station for the president's 8pm remarks.

Fox News Channel's Mike Emanuel contributed to this report.