OED ends

U.S. Marines supporting Operation Enduring Freedom forcibly enter a compound in Afghanistan during sweep operations in 2004 after the owner refused to open up. OEF officially came to a close Dec. 28.
Photo Credit: Cpl. Jemssy Alvarez Jr./Marine Corps

Operation Enduring Freedom, the worldwide combat mission launched shortly after the terrorist attacks of Sept. 11, 2001, that eventually became synonymous with the 13-year war in Afghanistan, officially ended Sunday.

The mission that took the lives of 2,356 U.S. service members was punctuated with a ceremony with military officials in Kabul and a statement from President Obama lauding the efforts of those involved.

"On this day we give thanks to our troops and intelligence personnel who have been relentless against the terrorists responsible for 9/11 — devastating the core al Qaeda leadership, delivering justice to Osama bin Laden, disrupting terrorist plots and saving countless American lives. We are safer, and our nation is more secure, because of their service," Obama said in the written statement.

Up to 10,800 U.S. troops will remain in Afghanistan in 2015 and the mission will be renamed "Operation Freedom's Sentinel." Military officials say that will be a narrowly defined two-prong mission: advising the Afghan army and continuing to mount counterterrorism operations against the Taliban and other insurgents who may pose a threat to the U.S. or Afghan governments.

Obama's current strategy calls for reducing the U.S. force level to about 5,000 in 2016 until a complete end of the military mission there before he leaves the White House in 2017.

The early years of OEF encompassed missions around the world. Many U.S. troops supporting the invasion of Iraq in 2003 were technically deployed under OEF orders. And it also included counterterrorism operations in Southeast Asia, North Africa and elsewhere.

For years, the war operations in Afghanistan were comparatively small. U.S. troop levels there remained below 30,000 until 2008, when the Taliban insurgency began gaining ground and threatening the American-backed government. U.S. troop levels peaked at around 100,000 in 2010.

Pessimism about the military mission in Afghanistan has grown during the past several years.

According to a Military Times reader survey, the percentage of active-duty service members who say the U.S. ultimately is "very likely" or "somewhat likely" to succeed in Afghanistan has dropped from 76 percent in 2007 to 23 percent in 2014.

A similar trend is reported among civilians. While the mission was overwhelmingly popular when it began in October 2001, a Gallup Poll in 2014 showed that about half of Americans believe sending troops to Afghanistan was a mistake.