The Afghan hospital shooting that killed three Americans is the second "insider attack" by a member of Afghan security forces targeting civilians from allied countries this month and one of scores against allied foreigners, including troops, in the past eight years.
The number of insider attacks reached record levels in 2012 when 37 attacks by rogue Afghan security forces on coalition troops left 51 people dead — 32 of them U.S. troops, according to a Pentagon report.
The Pentagon reported two attacks in 2007, two in 2008, six in 2009, 11 in 2010, 20 in 2011 and 37 in 2012.
A look at some attacks on U.S. citizens and troops in Afghanistan:
April 4, 2014: An Afghan police officer shot two Associated Press staffers working in the eastern province of Khost, killing photographer Anja Niedringhaus and wounding veteran correspondent Kathy Gannon.
Feb. 12, 2014: Two U.S. soldiers were killed and four wounded in an attack by gunmen wearing Afghan security force uniforms in eastern Afghanistan.
Sept. 21, 2013: A gunman wearing the uniform of the Afghan National Security Forces turned his weapon against U.S. troops, killing three in eastern Gardez. The attack took place inside a base of the Afghan army.
Dec. 24, 2012: An American civilian adviser was killed by a female member of the Afghan police.
Aug. 27, 2012: Two U.S. troops were killed by an Afghan soldier in eastern Afghanistan. On the same day, 10 Afghan soldiers were killed when members of their own unit opened fire on them at an army post in southern Helmand province
Aug. 10, 2012: An Afghan police officer killed three Marines he had invited to a meal in Helmand province. That same day, three Marines assigned to a training unit were killed by an Afghan policeman.
Contributing: Associated Press