WASHINGTON (AP) — U.S. and British forces began launching airstrikes into Afghanistan on Oct. 7, 2001, in the wake of the 9/11 terrorist attacks against America. The initial strikes were aimed at Taliban troops, training camps and air defenses. By early November there were about 1,300 U.S. troops in Afghanistan.
Since then the U.S. force there has grown, reaching 100,000 in mid-2010 as President Barack Obama ordered additional troops sent in to quell escalating violence.
A snapshot look at the U.S. troop commitment to the war:
—Oct. 7, 2001: U.S. invades Afghanistan with massive air campaign.
—November 2001: 1,300 troops are in the country as commandos and ground troops, largely Marines, begin to arrive.
—December 2001: The U.S. force grows to 2,500 as troops scour and bombard the mountainous Tora Bora region for Osama bin Laden. Tribal leader Hamid Karzai is sworn in as chairman of the interim government.
—March 2002: 7,200 U.S. troops are in Afghanistan as U.S. leads Operation Anaconda, the largest ground assault of the war up to that point.
—December 2002: The U.S. ends the year with about 9,700 troops in Afghanistan, largely going after Taliban insurgents.
—December 2003: The U.S. ends the year with about 13,100 troops in Afghanistan.
—April 2004: U.S. troop numbers grow to 20,300 as the spring offensive looms and the U.S. builds up forces along the Afghan-Pakistan border and works to provide security for fledgling reconstruction projects.
—December 2006: U.S. force remains a bit more than 20,000, as attention has shifted to the escalating war in Iraq. Troops are concentrated in Taliban strongholds in the south and east, where fighting is fiercest.
—December 2007: U.S. forces climb to about 25,000 as Joint Chiefs Chairman Adm. Mike Mullen asserts that Iraq is the priority and the Afghanistan war is an "economy of force" operation.
—May 2009: U.S. troops levels surpass 50,000 as fighting intensifies and additional forces begin flowing in.
—December 2009: Troop level is more than 67,000; Obama orders 33,000 U.S. more troops to Afghanistan amid deteriorating security, escalating violence and troop deaths. Obama gives the Pentagon authority to deploy up to 102,000 to the war.
—August 2010: The additional troops are in, U.S. force size hits 100,000.
—May 2, 2011: Bin Laden is killed in Pakistan; U.S. troop levels in Afghanistan still hover around 100,000.
—June 22, 2011: Obama announces withdrawal plan.
—September 2012: Troop levels fall to 77,000, as the final surge troops prepare to leave Afghanistan.
—December 2013: There are about 46,000 U.S. troops in Afghanistan, as the drawdown continues.
—March 2014: Obama orders the military to develop options for a complete U.S. military withdrawal from Afghanistan because Afghan President Hamid Karzai refuses to sign a security agreement.
—May 2014: There are about 32,800 U.S. troops in Afghanistan.