As U.S. Troops Searched Afghans, a Bomber in the Crowd Moved In

Officials are still piecing together the chain of events in the attack that killed scores of people, including 13 U.S. service members, outside the Kabul airport.

WASHINGTON — The suicide bomber waited until the last possible moment, U.S. officials said. A crowd straining to get into Hamid Karzai International Airport had converged on Abbey Gate, a main entryway manned by Marines and other service members. The troops knew that they could be targeted in an attack; just the day before, the State Department had warned of a “credible” threat at three gates at the airport, where more than 5,000 American troops had helped to evacuate more than 100,000 people in less than two weeks. Abbey Gate was on the list. Airport security had closed two of the gates, but decided to leave Abbey Gate open, U.S. officials said.