President Barack Obama is expected to announce plans for the withdrawal of some 30,000 American troops sent to Afghanistan in a surge announced in 2009.

The president is to lay out his plans for Afghanistan in an address to the nation Wednesday, nearly a decade after the war began.

In the evening speech from the White House, Mr. Obama is expected to call for an initial withdrawal of 10,000 American troops by the end of this year, with the remainder of the surge to leave Afghanistan by late 2012.

White House spokesman Jay Carney says the president will explain how he will implement the strategy he outlined for Afghanistan in December 2009, when he approved the surge of 30,000 troops and promised the first American forces would leave in 18 months.

Carney called early reports of the size and speed of the withdrawal “speculation.”

President Obama is also expected to reaffirm the U.S. and NATO commitment to transfer security responsibilities to Afghan forces by 2014. The United States currently has about 100,000 troops in Afghanistan, and media reports estimate the U.S. government is spending $10 billion each month fighting the war.

U.S. opinion surveys indicate that Americans are increasingly weary and disillusioned about the war. A Pew Research poll released Tuesday shows a record 56 percent of Americans say U.S. troops should be brought home as soon as possible.

Defense Secretary Robert Gates said Tuesday the president has to take into account sustainability at home, both in Congress and among the American public, as well as conditions on the ground in Afghanistan.

Gates acknowledged the concerns about Afghanistan, saying the American people are “tired of a decade of war.” He noted there are “a lot of reservations” in Congress about the war and the level of U.S. commitment.

Hours before Mr. Obama's speech Wednesday, lawmakers in Congress passionately debated the costs and benefits of the war.

White House spokesman Carney said the president has remained focused on achieving his objectives in Afghanistan — disrupting, dismantling and defeating al-Qaida, reversing Taliban momentum, and preventing Afghanistan from becoming a safe haven for terrorists.