The top US and NATO military commander in Afghanistan may seek additional American troops to help local forces as they struggle to contain the Taliban insurgency, USA Today reported Tuesday.

General John Campbell's interview with the newspaper comes as the security situation in Afghanistan has deteriorated in the second half of 2015, with an increase in insurgent attacks and higher casualties among both Taliban and national forces.

Already, President Barack Obama has backtracked on a pledge to pull out all but 1,000 troops, and in October he announced that 9,800 US forces would remain in Afghanistan until the end of 2016.

Campbell told USA today he would ask the Obama administration to keep that higher number of troops in country as long as possible and suggested he might call for more US personnel.

"If I don't believe that we can accomplish the train, advise and assist and the (counter-terrorism) missions, then I owe it to the senior leadership to come back and say, 'Here's what I need.' If that's more people, it's more people," Campbell told the newspaper.

The 9,800 US troops are scheduled to be drawn down to 5,500 by January 1, 2017.

"My intent would be to keep as much as I could, for as long as I could," Campbell said.

This month marks a year since the US and NATO-led mission in Afghanistan transitioned into an Afghan operation, with allied nations assisting in training and equipping local forces to tackle Taliban and other groups.

The Taliban have already dealt some stinging blows to Afghan forces, including a short-lived takeover of the northern city of Kunduz.