The US military is taking a serious look at resupplying combat troops in Afghanistan using unmanned aircraft.

Faced with the task of delivering vast amounts of supplies by land and by air to troops in the mountainous, land-locked country, senior officers were considering using pilotless aircraft to help with the job, said US Air Force General Duncan McNabb.

After talks with the US Marine Corps, General McNabb said his transportation command had acquired a number of drones for possible supply missions.

"We bought some, to see how that would work," he said.

The general said drones could ferry smaller-scale cargo and retrieve global positioning system (GPS) receivers left behind when supplies are airdropped.

"You might be able to, for instance, not only deliver medicines and smaller kinds of cargo, you could also use it to bring back out the GPS receiver," he said.

Pallets dropped from military aircraft are guided to ground using GPS receivers and sophisticated software. But retrieving the receivers can pose a headache.

With the amount of airdropped cargo growing, using drones could make "the cost of an air drop pretty cheap" and offered an "exciting" prospect, according to General McNabb.

But he did not say when his command might be ready to launch drone supply missions.

The military and spy agencies have dramatically expanded the use of unmanned aircraft in recent years, using them mainly for intelligence gathering as well as for attacks on insurgents in Iraq and Afghanistan and Al Qaeda leaders in Pakistan.

- AFP