The US military has also used drones in Somalia, Yemen, Pakistan, Libya, and Iraq.
Washington claims that its airstrikes target militants, but local sources say civilians have been the main victims of the attacks.
The United Nations has called the US drone attacks targeted killings that flout international law.
The aerial attacks were initiated by former US President George W. Bush but have been escalated under President Barack Obama.
Insecurity continues to rise across Afghanistan, despite the presence of about 130,000 US-led forces in the war-torn country.