More than three weeks after attacks in this city killed the U.S. ambassador to Libya and three other Americans, sensitive documents remained only loosely secured in the remains of the U.S. mission here on Wednesday, offering visitors easy access to delicate details about American operations in Libya.

Documents detailing weapons collection efforts, emergency evacuation protocols, the full internal itinerary of Ambassador J. Christopher Stevens’s trip and the personnel records of Libyans who were contracted to secure the mission were among the items scattered across the floors of the looted compound when a Washington Post reporter and a translator visited Wednesday.