KABUL - The U.S. and NATO ceremonially ended their combat mission in Afghanistan on Monday, 13 years after the Sept. 11 terror attacks sparked their invasion of the country to topple the Taliban-led government.

NATO's International Security Assistance Force Joint Command, which was in charge of combat operations, lowered its flag, formally ending its deployment.

U.S. Gen. John F. Campbell, commander of NATO and U.S. forces, said that the mission now would transition to a training and support role for Afghanistan's own security forces, which have led the fight against the Taliban insurgents since mid-2013.

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

From Jan. 1, the coalition will maintain a force of 13,000 troops in Afghanistan, down from a peak around 140,000 in 2011. There are around 15,000 troops now in the country.

The mission ends as the Taliban is increasing its attacks. U.S. President Barack Obama recently allowed U.S. forces to launch operations against both Taliban and al-Qaida militants, broadening the mission of the U.S. forces that will remain in the country after the end of the year.

Violence continued Monday in the country, as suicide bombers launched an assault on a police station in southern Kandahar province. Police killed three suicide bombers, said Samim Akhplwak, the spokesman for the provincial governor. He said casualty figures were unclear.

Campbell said that Afghan security forces, including the army, police and local militias, were capable of securing the country despite record-high casualty figures that have risen 6.5 per cent this year, to 4,634 killed in action, compared to 4,350 in 2013. By comparison, some 3,500 foreign forces, including at least 2,210 American soldiers, have been killed since the war began in 2001.

Up to 10,800 U.S. troops will remain in Afghanistan for the first three months of next year, 1,000 more than previously planned as the new mission, called Resolute Support, waits for NATO partners to deploy, said a NATO official who spoke on condition of anonymity to discuss troop deployments.

As a result, there will be little, if any, net drop in U.S. troop numbers between now and Dec. 31. By the end of 2015, however, the U.S. troop total is to shrink to 5,500, and to near zero by the end of 2016.

Monday's ceremony was the first of two that will draw a formal close to NATO's combat mission by Dec. 28.

News from © The Associated Press, 2014