Dec. 8, 2014 - International Security Assistance Force Joint Command (IJC), Lieutenant General Joseph Anderson, left, folds the flag of IJC during a flag-lowering ceremony at Kabul International Airport in Afghanistan. The U.S. and NATO ceremonially ended their combat mission in Afghanistan Monday, 13 years after the Sept. 11 terror attacks sparked their invasion of the country.(AP)

Dec. 8, 2014 - International Security Assistance Forces take part in a ceremony at Kabul International Airport in Afghanistan. The U.S. and NATO ceremonially ended their combat mission in Afghanistan Monday, 13 years after the Sept. 11 terror attacks sparked their invasion of the country.(AP)

December 7, 2014: US military forces listen to U.S. Secretary of Defense Chuck Hagel speaking at Tactical Base Gamberi in eastern Afghanistan. Hagel was winding up a two day visit, his last to Afghanistan as secretary of defense. (AP Photo/Mark Wilson, Pool)

The U.S. and NATO closed their combat command in Afghanistan on Monday, more than 13 years after invading the country in the wake of the Sept. 11 terror attacks to target al Qaeda and Osama bin Laden.

Though quickly routing the Taliban-led government that sheltered the militants, the U.S.-led coalition soon found itself spending billions of dollars rebuilding a country devastated by almost 30 years of war while an insurgency grew as the invasion and occupation of Iraq quickly took America's attention.

As NATO's International Security Assistance Force's Joint Command, which was in charge of combat operations, lowered its flag Monday and formally ended its deployment, resurgent Taliban militants launched yet another bloody attack in the country. And with President Barack Obama allowing American troops to go after both al Qaeda and Taliban militants in the country into the next year, the fighting likely won't be over anytime soon.

"I don't think the war will slow or stop during the winter, as attacks on cities are not contingent on the weather," Afghan political analyst Wahid Muzhdah said. "I believe attacks in the cities will increase -- they attract media attention."

Monday's ceremony saw the NATO flag of the command folded and put away amid the foreign troop withdrawal. From Jan. 1, the coalition will maintain a force of 13,000 troops in Afghanistan, down from a peak around 140,000 in 2011. As of Dec. 1, there were some 13, 300 NATO troops in the country.

U.S. Gen. John F. Campbell, commander of NATO and U.S. forces, said foreign troops now will focus on training and supporting local Afghan forces, which have led the fight against the Taliban insurgents since mid-2013.

"The Afghan security forces are capable," Campbell told The Associated Press. "They have to make some changes in the leadership which they're doing, and they have to hold people accountable."

Read more:

More militant violence as US, NATO forces mark end of Afghan combat mission