The suicide bomber attack Thursday on crowds of Afghans flocking to Kabul's airport killed at least 60 Afghans and 13 U.S. troops. It was one of the deadliest days for U.S. troops in the country in the history of the 20-year conflict.\nSome of the deadliest days for U.S. troops in Afghanistan:\n\nAug. 26, 2021: Two suicide bombers and gunmen attack crowds of Afghans flocking to Kabul's airport in the waning days of an airlift for those fleeing the Taliban takeover. The attacks kill at least 60 Afghans and 13 U.S. troops.\nDec. 21, 2015: A suicide attacker rams an explosives-laden motorcycle into a joint NATO-Afghan patrol, killing six American troops. The soldiers were targeted as they moved through a village near Bagram Airfield.\nOct. 2, 2015: 11 people, including six U.S. service members, are killed when a U.S. Air Force C-130J transport plane crashes.\nDec. 17, 2013: Six U.S. service members are killed when a helicopter crashes.\nMay 4, 2013: Seven U.S. soldiers and a member of the NATO-led coalition are killed as the Taliban continued attacks as part of their spring offensive.\nMarch 11, 2013: A helicopter crash in southern Afghanistan kills five American service members. Two U.S. special operations forces were gunned down hours earlier in an insider attack by an Afghan policeman in eastern Afghanistan.\nAug. 6, 2011: A helicopter is shot down by an insurgent armed with a rocket-propelled grenade, killing 30 American troops and eight Afghans.\nMay 26, 2011: Nine NATO service members are killed, including seven U.S. troops who died when a bomb exploded in a field where they were patrolling on foot.\nApril 19, 2011: An Afghan officer kills eight U.S. airmen and one U.S. civilian during a routine meeting at an Afghan air force headquarters compound in Kabul.\nSept. 21, 2010: A helicopter crashed in a rugged section of southern Afghanistan, killing nine. The Defense Department said three were Navy SEALs and one was assigned to the Naval Special Warfare unit. Five were soldiers from the 101st Combat Aviation Brigade, 101st Airborne Division, at Fort Campbell, Ky.\nAug. 27, 2010: Homemade bombs kill three U.S. troops in southern and eastern Afghanistan.\nJune 8, 2010: Seven American troops, two Australians and a French Legionnaire are killed. A U.S. contractor training Afghan police also died in a suicide attack.\nOct. 27, 2009: Eight American troops die in two separate bomb attacks in southern Afghanistan.\nOct. 26, 2009: 11 American soldiers are killed in separate helicopter crashes. One chopper goes down in western Afghanistan, killing seven soldiers and three civilians working for the U.S. government. In a separate incident in the south, two other U.S. choppers collide while in flight, killing four American troops.\nOct. 3, 2009: Eight U.S. soldiers are killed when their outpost in Kamdesh, Nuristan, is attacked by as many as 300 militants. Another soldier dies in Wardak province when a bomb detonates while he attempts to disarm it.\nJuly 13, 2008: Nine American soldiers are killed when their remote outpost in Wanat, Nuristan, is attacked by small-arms fire and rocket-propelled grenades. Another soldier dies in Kajaki Sofla when his vehicle strikes a roadside bomb.\nFeb. 18, 2007: A U.S. helicopter crashes in the Shahjoi district of Zabul province, killing eight American troops.\nMay 5, 2006: 10 American soldiers die in a CH-47 Chinook helicopter crash during combat operations in eastern Afghanistan.\nJune 28, 2005: 16 U.S. troops on a special forces helicopter are killed when their MH-47 Chinook helicopter is shot down by insurgents. Three U.S. sailors also die the same day.\nApril 6, 2005: 15 U.S. service members and three American civilians are killed when their helicopter goes down in a sandstorm while returning to the main U.S. base at Bagram.\nJan. 29, 2004: An explosion at a weapons cache kills eight U.S. soldiers.\nMarch 23, 2003: A U.S. Air Force helicopter on a mercy mission to help two injured Afghan children crashes in southeastern Afghanistan, killing all six people aboard.\nMarch 4, 2002: Seven American soldiers are killed when two helicopters come under fire.\nJan. 9, 2002: A U.S. military refueling plane that was resupplying troops in Afghanistan crashes in Pakistan, killing all seven Marines aboard.