The increased reliance on unmanned aircraft strikes may be in part due to a reduction in the number of U.S. troops in Afghanistan, the Los Angeles Times reported Thursday.
"With fewer troops, and even with fewer manned aircraft flying overhead, it's harder to get traditional support in combat missions," said Joshua Foust, an analyst in Washington who has advised the U.S. military in Afghanistan.
"Drones provide a good way to do that without importing a bunch of pilots and the support infrastructure they'd need to remain based there."
Officers familiar with military operations in Afghanistan told the Times a growing number of Reaper and Predator drones available in the country and better availability of live video feeds could also explain the increase.
The increase in drone missions, which accounted for 5 percent of U.S. air attacks in 2011 and 12 percent in 2012, coincides with U.S. President Barack Obama's shift in strategy to have a smaller military footprint in its pursuit of Taliban and al-Qaida fighters, the newspaper reported.
Officials defending the use of drones say they are more accurate and less likely to cause civilian casualties. U.N. figures indicate there was a 42 percent reduction in civilian casualties caused by airstrikes in 2012.
One U.S. officer, whose name wasn't reported, told the Times though there are times when civilians may be inadvertently killed if they are too close to a location where an airstrike is carried out.