In Yemen, 223 people have been killed by 40 US drone strikes this year, up from 10 airstrikes in 2011.
According to the Long War Journal database, an estimated 19 percent of those killed were civilians.
One of the Obama administration's core principles in its counterterrorism policies is that the use of force should not increase recruits for terrorist organizations where the US strikes with drones, reported the Council on Foreign Relations. State Department coordinator for counterterrorism Daniel Benjamin emphasized in 2010: "We are eager to ensure that whatever policies we pursue do not result in one terrorist being taken off the street while 10 more are galvanized to take action."
More from GlobalPost: Al Qaeda offers bounty for killing US ambassador in Sanaa
Deputy national security advisor for counterterrorism John Brennan also ensured that the significant growth in US airstrikes in Yemen had not had this effect, stating in Foreign Policy: "Contrary to conventional wisdom, we see little evidence that [drone strikes] are generating widespread anti-American sentiment or recruits for AQAP. In fact, we see the opposite…Targeted strikes against the most senior and most dangerous AQAP terrorists are not the problem–they are part of the solution."
GlobalPost previously reported that the Yemen branch of al Qaeda had said it would pay three kilograms of gold — worth approximately $160,000 — to anyone who killed the US ambassador in Sanaa. The group also offered $23,000 to anyone who killed an American soldier inside Yemen.